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pub use super::listener::ListenerStatistics;
use std::time::Duration;
/// SRT provides a powerful set of statistical data on a socket. This data can be used to keep an eye
/// on a socket's health and track faulty behavior.
///
/// Statistics are calculated independently on each side (receiver and sender) and are not exchanged
/// between peers unless explicitly stated.
#[derive(Debug, Eq, PartialEq, Default, Clone)]
#[non_exhaustive]
pub struct SocketStatistics {
/// The time elapsed, in milliseconds, since the SRT socket was created.
pub elapsed_time: Duration, // msTimeStamp
pub tx_all_packets: u64,
pub rx_all_packets: u64,
pub tx_all_bytes: u64,
pub rx_all_bytes: u64,
pub tx_encrypted_data: u64,
pub rx_decrypted_data: u64,
pub rx_clock_adjustments: u64,
pub rx_clock_drift_mean: i64,
pub rx_clock_drift_stddev: i64,
pub rx_ack2_errors: i64,
/// The total number of sent DATA packets, including retransmissions ([tx_retransmit_data](#tx_retransmit_data)).
//
// TODO: Should we do this too?
// If the SRTO_PACKETFILTER socket option is enabled (refer to SRT API Socket Options), this statistic counts sent packet filter control packets (pktSndFilterExtraTotal) as well. Introduced in SRT v1.4.0.
pub tx_data: u64, // pktSentTotal
/// The total number of received DATA packets, including retransmissions ([rx_retransmit_data](#tx_retransmit_data)).
//
// TODO: Should we do this too?
// If the `SRTO_PACKETFILTER` socket option is enabled (refer to [SRT API Socket Options](API-socket-options.md)), this statistic counts received packet filter control packets ([pktRcvFilterExtraTotal](#pktRcvFilterExtraTotal)) as well. Introduced in SRT v1.4.0.
pub rx_data: u64, // pktRecvTotal
/// The total number of sent *unique* DATA packets.
///
/// This value contains only *unique* *original* DATA packets. Retransmitted DATA packets
/// ([tx_retransmit_data](#tx_retransmit_data)) are not taken into account.
///
/// This value corresponds to the number of original DATA packets sent by the SRT sender. It
/// counts every packet sent over the network for the first time, and can be calculated as
/// follows: `tx_unique_data = tx_data – tx_retransmit_data`. The original DATA packets are sent
/// only once.
//
// TODO: Should we do this?
// or by `pktSentUniqueTotal = pktSentTotal – pktRetransTotal - pktSndFilterExtraTotal` if the `SRTO_PACKETFILTER` socket option is enabled
// If the `SRTO_PACKETFILTER` socket option is enabled (refer to [SRT API Socket Options](API-socket-options.md)), packet filter control packets ([pktSndFilterExtraTotal](#pktSndFilterExtraTotal)) are also not taken into account.
pub tx_unique_data: u64, // pktSentUniqueTotal
/// The total number of received *unique* original, retransmitted or recovered DATA packets
/// *received in time*, *decrypted without errors* and, as a result, scheduled for delivery to
/// the upstream application by the SRT receiver.
///
/// Unique means "first arrived" DATA packets. There is no difference whether a packet is
/// original or, in case of loss, retransmitted or recovered by the packet filter. Whichever
/// packet comes first is taken into account.
///
/// This statistic doesn't count
///
/// - duplicate packets (retransmitted or sent several times by defective hardware/software),
/// - arrived too late packets (retransmitted or original packets arrived out of order) that
/// were already dropped by the TLPKTDROP mechanism (see [tx_dropped_data](#tx_dropped_data)
/// statistic),
/// - arrived in time packets, but decrypted with errors (see [rx_decrypt_errors](#rx_decrypt_errors)
/// statistic), and, as a result, dropped by the TLPKTDROP mechanism (see [tx_dropped_data](#tx_dropped_data)
/// statistic).
//
// TODO: Should we do this?
// DATA packets recovered by the packet filter ([pktRcvFilterSupplyTotal](#pktRcvFilterSupplyTotal)) are taken into account if the `SRTO_PACKETFILTER` socket option is enabled (refer to [SRT API Socket Options](API-socket-options.md)). Do not mix up with the control packets received by the packet filter ([pktRcvFilterExtraTotal](#pktRcvFilterExtraTotal)).
pub rx_unique_data: u64, // pktRecvUniqueTotal
/// The total number of data packets considered or reported as lost at the sender side. Does not
/// correspond to the packets detected as lost at the receiver side.
///
/// A packet is considered lost in two cases:
/// 1. Sender receives a loss report (NAK) from a receiver.
/// 2. Sender initiates retransmission after not receiving an ACK packet for a certain timeout.
/// Refer to `FASTREXMIT` and `LATEREXMIT` algorithms.
pub tx_loss_data: u64, // pktSndLossTotal
/// The total number of SRT DATA packets detected as presently missing (either reordered or lost)
/// at the receiver side.
///
/// The detection of presently missing packets is triggered by a newly received DATA packet with
/// the sequence number `s`. If `s` is greater than the sequence number `next_exp` of the next
/// expected packet (`s > next_exp`), the newly arrived packet `s` is considered in-order and
/// there is a sequence discontinuity of size `s - next_exp` associated with this packet. The
/// presence of sequence discontinuity means that some packets of the original sequence have
/// not yet arrived (presently missing), either reordered or lost. Once the sequence discontinuity
/// is detected, its size `s - next_exp` is added to `rx_loss_data` statistic. Refer to
/// [RFC 4737 - Packet Reordering Metrics](https://tools.ietf.org/html/rfc4737) for details.
///
/// If the packet `s` is received out of order (`s < next_exp`), the statistic is not affected.
///
/// Note that only original (not retransmitted) SRT DATA packets are taken into account. Refer to
/// [rx_retransmit_data](#rx_retransmit_data) for the formula for obtaining the total number of
/// lost retransmitted packets.
//
// TODO: ensure this is implemented correctly
// In SRT v1.4.0, v1.4.1, the `pktRcvLossTotal` statistic includes packets that failed to be decrypted. To receive the number of presently missing packets, substract [pktRcvUndecryptTotal](#pktRcvUndecryptTotal) from the current one. This is going to be fixed in SRT v.1.5.0.
pub rx_loss_data: u64, // pktRcvLossTotal
/// The total number of retransmitted packets sent by the SRT sender.
///
/// This statistic is not interchangeable with the receiver [rx_retransmit_data](#rx_retransmit_data)
/// statistic.
pub tx_retransmit_data: u64, // pktRetransTotal
/// The total number of retransmitted packets registered at the receiver side.
///
/// This statistic is not interchangeable with the sender [tx_retransmit_data](#tx_retransmit_data)
/// statistic.
///
/// Note that the total number of lost retransmitted packets can be calculated as the total
/// number of retransmitted packets sent by receiver minus the total number of retransmitted
/// packets registered at the receiver side: `tx_retransmit_data - rx_retransmit_data`.
//
// TODO: ensure this is implemented correctly
// This is going to be implemented in SRT v1.5.0, see issue [#1208](https://github.com/Haivision/srt/issues/1208).
pub rx_retransmit_data: u64, // pktRcvRetransTotal
/// The total number of sent ACK (Acknowledgement) control packets.
pub tx_ack: u64, // pktSentACKTotal
/// The total number of received ACK (Acknowledgement) control packets.
pub rx_ack: u64, // pktRecvACKTotal
pub tx_light_ack: u64,
pub rx_light_ack: u64,
/// The total number of sent NAK (Negative Acknowledgement) control packets.
pub tx_nak: u64, // pktSentNAKTotal
/// The total number of received NAK (Negative Acknowledgement) control packets.
pub rx_nak: u64, // pktRecvNAKTotal
/// The total number of sent ACK2 (Acknowledgement Acknowledgement) control packets.
pub tx_ack2: u64,
/// The total number of received ACK2 (Acknowledgement Acknowledgement) control packets.
pub rx_ack2: u64,
/// The total accumulated time, during which the SRT sender has some data to
/// transmit, including packets that have been sent, but not yet acknowledged. In other words,
/// the total accumulated duration in microseconds when there was something to deliver (non-empty
/// senders' buffer).
pub tx_buffer_time: Duration, // usSndDurationTotal
/// The total number of DATA packets _dropped_ by the SRT sender that have no chance to be
/// delivered in time (refer to [TLPKTDROP](https://github.com/Haivision/srt-rfc/blob/master/draft-sharabayko-mops-srt.md#too-late-packet-drop-too-late-packet-drop)
/// mechanism).
///
/// Packets may be dropped conditionally when both `SRTO_TSBPDMODE` and `SRTO_TLPKTDROP` socket
/// options are enabled, refer to [SRT API Socket Options](API-socket-options.md).
///
/// The delay before TLPKTDROP mechanism is triggered is calculated as follows
/// `SRTO_PEERLATENCY + SRTO_SNDDROPDELAY + 2 * interval between sending ACKs`,
/// where `SRTO_PEERLATENCY` is the configured SRT latency, `SRTO_SNDDROPDELAY` adds an extra to
/// `SRTO_PEERLATENCY` delay, the default `interval between sending ACKs` is 10 milliseconds. The
/// minimum delay is `1000 + 2 * interval between sending ACKs` milliseconds.
//
// TODO: Should we provide these configuration options?
// Refer to `SRTO_PEERLATENCY`, `SRTO_SNDDROPDELAY` socket options in [SRT API Socket Options](API-socket-options.md).
pub tx_dropped_data: u64, // pktSndDropTotal
/// The total number of DATA packets _dropped_ by the SRT receiver and, as a result, not delivered to the upstream application (refer to [TLPKTDROP](https://github.com/Haivision/srt-rfc/blob/master/draft-sharabayko-mops-srt.md#too-late-packet-drop-too-late-packet-drop) mechanism).
///
/// This statistic counts
/// - arrived too late packets (retransmitted or original packets arrived out of order),
/// - arrived in time packets, but decrypted with errors (see also [rx_decrypt_errors](#rx_decrypt_errors) statistic).
//
// TODO: Should we provide these configuration options?
// Packets may be dropped conditionally when both `SRTO_TSBPDMODE` and `SRTO_TLPKTDROP` socket options are enabled, refer to [SRT API Socket Options](API-socket-options.md).
pub rx_dropped_data: u64, // pktRcvDropTotal
/// The total number of packets that failed to be decrypted at the receiver side.
pub rx_decrypt_errors: u64, // pktRcvUndecryptTotal
// The total number of packet filter control packets generated by the packet filter (refer to [SRT Packet Filtering & FEC](../features/packet-filtering-and-fec.md)).
//
// Packet filter control packets contain only control information necessary for the packet filter. The type of these packets is DATA.
//
// If the `SRTO_PACKETFILTER` socket option is disabled (refer to [SRT API Socket Options](API-socket-options.md)), this statistic is equal to 0. Introduced in SRT v1.4.0.
//
// TODO: this probably won't be implemented; extensible packet filtering seems like over engineering
// #### pktSndFilterExtraTotal
// The total number of packet filter control packets received by the packet filter (refer to [SRT Packet Filtering & FEC](../features/packet-filtering-and-fec.md)).
//
// Packet filter control packets contain only control information necessary for the packet filter. The type of these packets is DATA.
//
// If the `SRTO_PACKETFILTER` socket option is disabled (refer to [SRT API Socket Options](API-socket-options.md)), this statistic is equal to 0. Introduced in SRT v1.4.0.
//
// TODO: this probably won't be implemented; extensible packet filtering seems like over engineering
// #### pktRcvFilterExtraTotal
// The total number of lost DATA packets recovered by the packet filter at the receiver side (e.g., FEC rebuilt packets; refer to [SRT Packet Filtering & FEC](../features/packet-filtering-and-fec.md)).
//
// If the `SRTO_PACKETFILTER` socket option is disabled (refer to [SRT API Socket Options](API-socket-options.md)), this statistic is equal to 0. Introduced in SRT v1.4.0.
//
// TODO: this probably won't be implemented; extensible packet filtering seems like over engineering
// #### pktRcvFilterSupplyTotal
// The total number of lost DATA packets **not** recovered by the packet filter at the receiver side (refer to [SRT Packet Filtering & FEC](../features/packet-filtering-and-fec.md)).
//
// If the `SRTO_PACKETFILTER` socket option is disabled (refer to [SRT API Socket Options](API-socket-options.md)), this statistic is equal to 0. Introduced in SRT v1.4.0.
//
// TODO: this probably won't be implemented; extensible packet filtering seems like over engineering
// #### pktRcvFilterLossTotal
/// Same as [tx_data](#tx_data), but expressed in bytes, including payload and all the headers
/// (20 bytes IPv4 + 8 bytes UDP + 16 bytes SRT).
pub tx_bytes: u64, // byteSentTotal
/// Same as [rx_data](#rx_data), but expressed in bytes, including payload and all the headers
/// (20 bytes IPv4 + 8 bytes UDP + 16 bytes SRT).
pub rx_bytes: u64, // byteRecvTotal
/// Same as [tx_unique_data](#tx_unique_data), but expressed in bytes, including payload and all
/// the headers (20 bytes IPv4 + 8 bytes UDP + 16 bytes SRT).
pub tx_unique_bytes: u64, // byteSentUniqueTotal
/// Same as [rx_unique_data](#tx_unique_data), but expressed in bytes, including payload and all
/// the headers (20 bytes IPv4 + 8 bytes UDP + 16 bytes SRT).
pub rx_unique_bytes: u64, // byteRecvUniqueTotal
/// Same as [rx_loss_data](#rx_loss_data), but expressed in bytes, including payload and all the
/// headers (20 bytes IPv4 + 8 bytes UDP + 16 bytes SRT). Bytes for the presently missing (either
/// reordered or lost) packets' payloads are estimated based on the average packet size.
pub rx_loss_bytes: u64, // byteRcvLossTotal
/// Same as [tx_retransmit_data](#tx_retransmit_data), but expressed in bytes, including payload
/// and all the headers (20 bytes IPv4 + 8 bytes UDP + 16 bytes SRT).
pub tx_retransmit_bytes: u64, // byteRetransTotal
/// Same as [tx_dropped_data](#tx_dropped_data), but expressed in bytes, including payload and
/// all the headers (20 bytes IPv4 + 8 bytes UDP + 16 bytes SRT).
pub tx_dropped_bytes: u64, // byteSndDropTotal
/// Same as [rx_dropped_data](#rx_dropped_data), but expressed in bytes, including payload and
/// all the headers (20 bytes IPv4 + 8 bytes UDP + 16 bytes SRT). Bytes for the dropped packets'
/// payloads are estimated based on the average packet size.
// TODO: do we really need this?
// this could be calculated based on rx_dropped_data * (tx_data_bytes / tx_data)
pub rx_dropped_bytes: u64, // byteRcvDropTotal
/// Same as [rx_decrypt_errors](#rx_decrypt_errors), but expressed in bytes, including payload
/// and all the headers (20 bytes IPv4 + 8 bytes UDP + 16 bytes SRT).
pub rx_decrypt_error_bytes: u64, // byteRcvUndecryptTotal
/// Current minimum time interval between which consecutive packets are sent microseconds.
///
/// The `tx_snd_period` is the minimum time (sending period) that must be kept between two
/// packets sent consecutively over the link used by an SRT socket. It is not the EXACT time
/// interval between two consecutive packets. In the case where the time spent by an application
/// between sending two consecutive packets exceeds `tx_snd_period`, the next packet will be
/// sent faster, or even immediately, to preserve the average sending rate.
///
/// **Note**: Does not apply to probing packets.
// TODO: This isn't true, should it be?
// Note that several sockets sharing one outgoing port use the same sending queue.
// They may have different pacing of the outgoing packets, but all the packets will
// be placed in the same sending queue, which may affect the send timing.
pub tx_snd_period: Duration, // usPktSndPeriod
/// The maximum number of packets that can be "in flight".
/// See also [tx_unacknowledged_data](#tx_unacknowledged_data).
///
/// The value retrieved on the sender side represents an estimation of the amount of free space
/// in the buffer of the peer receiver. The actual amount of available space is periodically
/// reported back by the receiver in ACK packets. When this value drops to zero, the next packet
/// sent will be dropped by the receiver without processing. The receiver buffer contents should
/// normally occupy no more than half of the buffer size (default 8192). If `tx_flow_window`
/// value is less than that and becomes even less in the next reports, it means that the receiver
/// application on the peer side cannot process the incoming stream fast enough and this may lead
/// to a dropped connection.
//
// TODO: Should we implement this?
// In **file mode** this may cause a slowdown of sending in
// order to wait until the receiver has more space available, after it
// eventually extracts the packets waiting in its receiver buffer; in **live
// mode**
pub tx_flow_window: u64, // pktFlowWindow
// Congestion window size, in number of packets.
//
// Dynamically limits the maximum number of packets that can be in flight.
// Congestion control module dynamically changes the value.
//
// In **file mode** this value starts at 16 and is increased to the number of reported
// acknowledged packets. This value is also updated based on the delivery rate, reported by the
// receiver. It represents the maximum number of packets that can be safely sent without causing
// network congestion. The higher this value is, the faster the packets can be sent.
// In **live mode** this field is not used.
// TODO: Should we implement this?
// it's only for file mode
// #### pktCongestionWindow
/// The number of packets in flight, therefore `tx_unacknowledged_data <= tx_flow_window`.
// TODO: Should we implement this?
// it's only for file mode
// and `tx_unacknowledged_data <= pktCongestionWindow`
///
/// This is the distance between the packet sequence number that was last reported by an ACK
/// message and the sequence number of the latest packet sent (at the moment when the statistics
/// are being read).
///
/// **NOTE:** ACKs are received periodically (at least every 10 ms). This value is most accurate
/// just after receiving an ACK and becomes a little exaggerated over time until the next ACK
/// arrives. This is because with a new packet sent, while the ACK number stays the same for a
/// moment, the value of `tx_unacknowledged_data` increases. But the exact number of packets
/// arrived since the last ACK report is unknown. A new statistic might be added which only
/// reports the distance between the ACK sequence and the sent sequence at the moment when an
/// ACK arrives, and isn't updated until the next ACK arrives. The difference between this value
/// and `tx_unacknowledged_data` would then reveal the number of packets with an unknown state
/// at that moment.
pub tx_unacknowledged_data: u64, // pktFlightSize
/// Smoothed round-trip time (SRTT), an exponentially-weighted moving average (EWMA) of an
/// endpoint's RTT samples, in milliseconds.
///
/// See [Section 4.10. Round-Trip Time Estimation](https://tools.ietf.org/html/draft-sharabayko-srt-00#section-4.10)
/// of the [SRT RFC](https://datatracker.ietf.org/doc/html/draft-sharabayko-srt-00)
/// and [[RFC6298] Paxson, V., Allman, M., Chu, J., and M. Sargent, "Computing TCP's Retransmission Timer"](https://datatracker.ietf.org/doc/html/rfc6298)
/// for more details.
pub tx_average_rtt: Duration, // msRTT
pub rx_average_rtt: Duration,
/// Estimated bandwidth of the network link.
///
/// The bandwidth is estimated at the receiver. The estimation is based on the time between two
/// probing DATA packets. Every 16th data packet is sent immediately after the previous data
/// packet. By measuring the delay between probe packets on arrival, it is possible to estimate
/// the maximum available transmission rate, which is interpreted as the bandwidth of the link.
/// The receiver then sends back a running average calculation to the sender with an ACK message.
pub tx_bandwidth: u64, // mbpsBandwidth
pub rx_bandwidth: u64,
/// The available space in the sender's buffer.
///
/// This value decreases with data scheduled for sending by the application, and increases with
/// every ACK received from the receiver, after the packets are sent over the UDP link.
pub tx_buffer_available_bytes: u64, // byteAvailSndBuf
/// The available space in the receiver's buffer, in bytes.
///
/// This value increases after the application extracts the data from the socket and decreases
/// with every packet received from the sender over the UDP link.
pub rx_buffer_available_bytes: u64, // byteAvailRcvBuf
// Transmission bandwidth limit, in Mbps.
// Usually this is the setting from
// the `SRTO_MAXBW` option, which may include the value 0 (unlimited). Under certain
// conditions a nonzero value might be be provided by a congestion
// control module, although none of the built-in congestion control modules
// currently use it.
//
// Refer to `SRTO_MAXBW` and `SRTO_INPUTBW` in [SRT API Socket Options](API-socket-options.md).
// TODO: Should we implement this?
// it's not actually dynamic, is it? if not then it's uninteresting as a statistic.
// #### mbpsMaxBW
// Maximum Segment Size (MSS), in bytes.
// Same as the value from the `SRTO_MSS` socket option.
// Should not exceed the size of the maximum transmission unit (MTU), in bytes. Sender and Receiver.
// The default size of the UDP packet used for transport,
// including all possible headers (Ethernet, IP and UDP), is 1500 bytes.
//
// Refer to `SRTO_MSS` in [SRT API Socket Options](API-socket-options.md).
// TODO: Should we implement this?
// it's not actually dynamic, is it? if not then it's uninteresting as a statistic.
// #### byteMSS
// The number of packets in the sender's buffer that are already scheduled for sending or even
// possibly sent, but not yet acknowledged.
//
// Once the receiver acknowledges the receipt of a packet, or the too late packet drop is
// triggered, the packet is removed from the sender's buffer. Until this happens, the packet is
// considered as unacknowledged.
// TODO: also calculate average
pub tx_buffered_data: u64, // pktSndBuf
// Instantaneous (current) value of `tx_buffered_data`, but expressed in bytes, including payload and
// all headers (SRT+UDP+IP). \
// 20 bytes IPv4 + 8 bytes of UDP + 16 bytes SRT header.
// TODO: also calculate average
pub tx_buffered_bytes: u64, // byteSndBuf
// The timespan of packets in the sender's buffer.
// TODO: also calculate average
pub tx_buffered_time: Duration, // msSndBuf
// Timestamp-based Packet Delivery Delay value of the peer.
// If `SRTO_TSBPDMODE` is on (default for **live mode**), it
// returns the value of `SRTO_PEERLATENCY`, otherwise 0.
// The sender reports the TSBPD delay value of the receiver.
// The receiver reports the TSBPD delay of the sender.
// TODO: Should we implement this?
// it's not actually dynamic, is it? if not then it's uninteresting as a statistic.
// #### msSndTsbPdDelay
/// The number of acknowledged packets in receiver's buffer.
///
/// This measurement does not include received but not acknowledged packets, stored in the
/// receiver's buffer.
// TODO: also calculate average
pub rx_acknowledged_data: u64, // pktRcvBuf
/// Instantaneous (current) value of `pktRcvBuf`, expressed in bytes, including payload and all
/// headers (SRT+UDP+IP). \
/// 20 bytes IPv4 + 8 bytes of UDP + 16 bytes SRT header.
// TODO: also calculate average
pub rx_acknowledged_bytes: u64, // byteRcvBuf
/// The timespan of acknowledged packets in the receiver's buffer.
///
/// A packet can be acknowledged, but not yet ready to play. This range includes all packets
/// regardless of whether they are ready to play or not.
/// TODO: also calculate average
pub rx_acknowledged_time: Duration, // msRcvBuf
// Timestamp-based Packet Delivery Delay value set on the socket via `SRTO_RCVLATENCY` or `SRTO_LATENCY`.
// The value is used to apply TSBPD delay for reading the received data on the socket.
//
// If `SRTO_TSBPDMODE` is off (default for **file mode**), 0 is returned.
// TODO: Should we implement this?
// it's not actually dynamic, is it? if not then it's uninteresting as a statistic.
// #### msRcvTsbPdDelay
// #### pktReorderDistance
//
// The distance in sequence numbers between the two original (not retransmitted) packets,
// that were received out of order.
// TODO: Should we implement this?
// should we even support maximum reorder tolerance?
// The traceable distance values are limited by the maximum reorder tolerance set by `SRTO_LOSSMAXTTL`.
// Instant value of the packet reorder tolerance. Receiver side. Refer to [pktReorderDistance](#pktReorderDistance).
//
// `SRTO_LOSSMAXTTL` sets the maximum reorder tolerance value. The value defines the maximum
// time-to-live for the original packet, that was received after with a gap in the sequence of incoming packets.
// Those missing packets are expected to come out of order, therefore no loss is reported.
// The actual TTL value (**pktReorderTolerance**) specifies the number of packets to receive further, before considering
// the preceding packets lost, and sending the loss report.
//
// The internal algorithm checks the order of incoming packets and adjusts the tolerance based on the reorder
// distance (**pktReorderTolerance**), but not to a value higher than the maximum (`SRTO_LOSSMAXTTL`).
//
// SRT starts from tolerance value set in `SRTO_LOSSMAXTTL` (initial tolerance is set to 0 in SRT v1.4.0 and prior versions).
// Once the receiver receives the first reordered packet, it increases the tolerance to the distance in the sequence
// discontinuity of the two packets. \
// After 10 consecutive original (not retransmitted) packets come in order, the reorder distance
// is decreased by 1 for every such packet.
//
// For example, assume packets with the following sequence
// numbers are being received: \
// 1, 2, 4, 3, 5, 7, 6, 10, 8, 9
// SRT starts from 0 tolerance. Receiving packet with sequence number 4 has a discontinuity
// equal to one packet. The loss is reported to the sender.
// With the next packet (sequence number 3) a reordering is detected. Reorder tolerance is increased to 1. \
// The next sequence discontinuity is detected when the packet with sequence number 7 is received.
// The current tolerance value is 1, which is equal to the gap (between 5 and 7). No loss is reported. \
// Next packet with sequence number 10 has a higher sequence discontinuity equal to 2.
// Missing packets with sequence numbers 8 and 9 will be reported lost with the next received packet
// (reorder distance is still at 1).
// The next received packet has sequence number 8. Reorder tolerance value is increased to 2.
// The packet with sequence number 9 is reported lost.
// TODO: Should we implement this?
// I don't think we've implemented SRTO_LOSSMAXTTL yet, revisit this when/if we do
// #### pktReorderTolerance
/// The number of packets received but IGNORED due to having arrived too late.
///
/// Makes sense only if TSBPD and TLPKTDROP are enabled.
///
/// An offset between sequence numbers of the newly arrived DATA packet and latest acknowledged
/// DATA packet is calculated. If the offset is negative, the packet is considered late, meaning
/// that it was either already acknowledged or dropped by TSBPD as too late to be delivered.
///
/// Retransmitted packets can also be considered late.
pub rx_belated_data: u64, // pktRcvBelated
/// Accumulated difference between the current time and the time-to-play of a packet that is
/// received late.
pub rx_belated_time: Duration, // pktRcvAvgBelatedTime
}
impl SocketStatistics {
pub fn new() -> Self {
Self::default()
}
}