Enum sage_mqtt::QoS [−][src]
pub enum QoS {
AtMostOnce,
AtLeastOnce,
ExactlyOnce,
}
Expand description
Description the quality of service used in message publishing.
Variants
AtMostOnce
The message is delivered according to the capabilities of the underlying network. No response is sent by the receiver and no retry is performed by the sender. The message arrives at the receiver either once or not at all.
AtLeastOnce
This Quality of Service level ensures that the message arrives at the
receiver at least once. A QoS 1 PUBLISH packet has a Packet Identifier
and is acknowledged by a Puback
packet.
ExactlyOnce
This is the highest Quality of Service level, for use when neither loss
nor duplication of messages are acceptable.
There is an increased overhead associated with QoS 2.
A QoS 2 message has a Packet Identifier. The receiver of a QoS 2
Publish
packet acknowledges receipt with a two-step
acknowledgement process.
Trait Implementations
Auto Trait Implementations
impl RefUnwindSafe for QoS
impl UnwindSafe for QoS
Blanket Implementations
Mutably borrows from an owned value. Read more