Struct StreamProtocolConfig 

pub struct StreamProtocolConfig {
    pub per_peer_channel_capacity: usize,
    pub stream_open_timeout: Duration,
    pub frame_writer_backpressure_bytes: usize,
    pub egress_backpressure_timeout: Duration,
}

Configuration of the per-peer egress stream layer.

Fields

per_peer_channel_capacity: usize

Capacity of the per-peer egress channel (in packets).

The egress drain enqueues each outgoing packet via try_send. When the channel is full the behaviour depends on the stream state: while the stream is still opening it drops the newest packet (a slow open for one peer must not head-of-line-block others); once the stream is open and its write pump is draining, it instead applies bounded backpressure — waiting up to EGRESS_BACKPRESSURE_TIMEOUT for space so wire-rate backpressure propagates upstream — and only drops the newest packet if the peer stays full past that timeout. The channel absorbs bursts while a stream is being opened; once open the write pump continuously drains it, so it stays near-empty under normal load.

Sized to absorb a typical SURB pre-fill burst (default SurbBalancer: target 7 000 / max 5 000/s).

Defaults to 5 000.

stream_open_timeout: Duration

Timeout for the NetworkStreamControl::open call when opening a new outgoing stream to a peer.

A timeout is mandatory: without it a permanently-unreachable peer would park the opener task indefinitely. When the open attempt fails or times out the buffered packets for that peer are dropped and a debug-level log entry is emitted. The cache entry is then invalidated so the next send triggers a fresh open attempt.

Must be at least 1 ms. Defaults to 2 seconds.

frame_writer_backpressure_bytes: usize

Pending-write-buffer byte threshold on the framed writer before a flush is forced.

A value of 1 flushes on every encoded frame (one syscall per message). Larger values coalesce adjacent small frames into a single quinn write call, reducing connection-mutex acquisitions and driver wake-ups on the hot path. A HOPR packet is ~1 440 bytes; at the default 128 KiB threshold roughly 91 packets are coalesced per write, cutting driver wake frequency ~30×.

Defaults to 131 072 bytes (128 KiB).

egress_backpressure_timeout: Duration

Maximum time the egress drain waits on a full — but open and draining — per-peer channel before falling back to drop-newest.

While the stream is open, a full channel means the wire is slower than the producer, so waiting here propagates wire-rate backpressure up through the mixer and session socket to the application writer (no packet loss). The bound ensures a single permanently-stalled peer cannot head-of-line-block delivery to other peers indefinitely: after this timeout the packet is dropped and the drain moves on. Healthy peers drain far faster than this, so the timeout is not hit in normal operation.

Defaults to 2 seconds. Must be at least 1 ms — a zero value would defeat the feature.

Trait Implementations

impl Clone for StreamProtocolConfig

fn clone(&self) -> StreamProtocolConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for StreamProtocolConfig

impl Debug for StreamProtocolConfig

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

Formats the value using the given formatter.

impl Default for StreamProtocolConfig

fn default() -> Self

Return StreamProtocolConfig { per_peer_channel_capacity: default_per_peer_channel_capacity(), stream_open_timeout: default_stream_open_timeout(), frame_writer_backpressure_bytes: default_frame_writer_backpressure_bytes(), egress_backpressure_timeout: default_egress_backpressure_timeout() }

impl Eq for StreamProtocolConfig

impl PartialEq for StreamProtocolConfig

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for StreamProtocolConfig

impl Validate for StreamProtocolConfig

fn validate(&self) -> Result<(), ValidationErrors>

impl<'v_a> ValidateArgs<'v_a> for StreamProtocolConfig

type Args = ()

fn validate_with_args(&self, args: Self::Args) -> Result<(), ValidationErrors>