Struct ydb_unofficial::generated::ydb::topic::stream_read_message::ReadRequest

pub struct ReadRequest {
    pub bytes_size: i64,
}

Message that represents client readiness for receiving more data.

Fields

bytes_size: i64

Server and client each keep track of total bytes size of all ReadResponses. When client is ready to receive N more bytes in responses (to increment possible total by N), it sends a ReadRequest with bytes_size = N. bytes_size value must be positive. So in expression ‘A = (sum of bytes_size in all ReadRequests) - (sum of bytes_size in all ReadResponses)’ server will keep A (available size for responses) non-negative. But there is an exception. If server receives ReadRequest, and the first message in response exceeds A - then it will still be delivered, and A will become negative until enough additional ReadRequests.

Example:

1. Let client have 200 bytes buffer. It sends ReadRequest with bytes_size = 200; 2) Server may return one ReadResponse with bytes_size = 70 and than another 80 bytes response; now client buffer has 50 free bytes, server is free to send up to 50 bytes in responses.
2. Client processes 100 bytes from buffer, now buffer free space is 150 bytes, so client sends ReadRequest with bytes_size = 100;
3. Server is free to send up to 50 + 100 = 150 bytes. But the next read message is too big, and it sends 160 bytes ReadResponse.
4. Let’s assume client somehow processes it, and its 200 bytes buffer is free again. It shoud account for excess 10 bytes and send ReadRequest with bytes_size = 210.

Trait Implementations

impl Clone for ReadRequest

fn clone(&self) -> ReadRequest

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ReadRequest

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for ReadRequest

fn default() -> ReadRequest

Returns the “default value” for a type.

impl Message for ReadRequest

fn encoded_len(&self) -> usize

Returns the encoded length of the message without a length delimiter.

fn clear(&mut self)

Clears the message, resetting all fields to their default.

fn encode<B>(&self, buf: &mut B) -> Result<(), EncodeError>where B: BufMut, Self: Sized,

Encodes the message to a buffer.

fn encode_to_vec(&self) -> Vec<u8, Global>where Self: Sized,

Encodes the message to a newly allocated buffer.

fn encode_length_delimited<B>(&self, buf: &mut B) -> Result<(), EncodeError>where B: BufMut, Self: Sized,

Encodes the message with a length-delimiter to a buffer.

fn encode_length_delimited_to_vec(&self) -> Vec<u8, Global>where Self: Sized,

Encodes the message with a length-delimiter to a newly allocated buffer.

fn decode<B>(buf: B) -> Result<Self, DecodeError>where B: Buf, Self: Default,

Decodes an instance of the message from a buffer.

fn decode_length_delimited<B>(buf: B) -> Result<Self, DecodeError>where B: Buf, Self: Default,

Decodes a length-delimited instance of the message from the buffer.

fn merge<B>(&mut self, buf: B) -> Result<(), DecodeError>where B: Buf, Self: Sized,

Decodes an instance of the message from a buffer, and merges it into self.

fn merge_length_delimited<B>(&mut self, buf: B) -> Result<(), DecodeError>where B: Buf, Self: Sized,

Decodes a length-delimited instance of the message from buffer, and merges it into self.

impl PartialEq<ReadRequest> for ReadRequest

fn eq(&self, other: &ReadRequest) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for ReadRequest