Module datagram 

Available on crate features http and std only.

HTTP Datagrams and the Capsule Protocol (RFC 9297), shared by every HTTP version.

HttpDatagramSession runs on the upgraded I/O of any successful HTTP/1.x upgrade or HTTP/2 and HTTP/3 Extended CONNECT. It sends DATAGRAM and control capsules on the reliable data stream and, when the transport publishes NativeDatagrams (HTTP/3 with negotiated QUIC DATAGRAM), unreliable native datagrams. handshake maps an upgrade token onto each HTTP version; nothing above the session needs a version switch.

Modules

capsule

Bounded, incremental Capsule Protocol decoding (RFC 9297 §3).

handshake

Upgrade-token handshakes for protocols that use the Capsule Protocol (RFC 9297 §3.2).

Structs

CapsuleObservation

An optional upgraded-I/O extension selecting a Capsule metadata observer. Works on reliable streams even when no native HTTP Datagram carrier is available.

DatagramRelayDirection

Counts for one completed forwarding direction. Native delivery is unreliable; accepting a send does not prove that the remote application received it.

DatagramRelayOutcome

Two independent directional outcomes; a clean half-close does not stop its sibling.

HttpDatagramRelay

Forward a tunnel whose application explicitly selected HTTP Datagram semantics.

HttpDatagramSession

An HTTP Datagram and Capsule Protocol session on an established request.

NativeDatagrams

A request’s native datagram carrier, published on the upgraded I/O’s extensions.

NativeSendReady

A wait for native send room, from NativeDatagramChannel::send_ready.

SessionConfig

Configuration of an HttpDatagramSession.

SessionReceiver

The receiving half of an HttpDatagramSession.

SessionSender

The sending half of an HttpDatagramSession.

Enums

DatagramTransport

How an HTTP Datagram travelled.

NativeRecvError

The receive side of a native association ended abnormally.

NativeSendError

A native datagram could not be handed to the transport.

NativeSendPolicy

How a native send behaves when the transport’s datagram buffer is full.

SessionError

A session operation failed.

SessionEvent

An event received on a session.

ViolationPolicy

How peer violations of HTTP Datagram rules that do not affect framing are handled.

Traits

CapsuleObserver

A synchronous metadata observer. Methods must finish promptly without I/O, blocking or reentering the session. Header metadata contains no value bytes. Retained data and callback failures belong to the observer; observations must not control protocol behavior.

NativeDatagramChannel

Unreliable delivery of HTTP Datagrams associated with one request, such as HTTP/3 QUIC DATAGRAM frames (RFC 9297 §2.1).