Enum Error 

#[non_exhaustive]
pub enum Error {
    Transport(String),
    Decode(DecodeError),
    Version,
    RequiredExtension,
    UnexpectedStream,
    BoundsExceeded(BoundsExceeded),
    Duplicate,
    Cancel,
    Timeout,
    Old,
    App(u16),
    NotFound,
    Unroutable,
    WrongSize,
    ProtocolViolation,
    Unauthorized,
    UnexpectedMessage,
    Unsupported,
    Encode(EncodeError),
    TooManyParameters,
    InvalidRole,
    UnknownAlpn(String),
    Dropped,
    Closed,
    Lagged,
    FrameTooLarge,
    TimestampMismatch,
    Evicted,
    Remote(u32),
}

A list of possible errors that can occur during the session.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Transport(String)

The underlying QUIC/WebTransport connection failed; carries the backend’s message.

Decode(DecodeError)

A message off the wire could not be parsed.

Version

Version negotiation failed, or the negotiated version lacks a requested feature (e.g. a FETCH against a version without fetch support). Mostly a connect-time error, but the feature-gap case can surface mid-session, so it can’t simply move to a connect-only error type.

RequiredExtension

A required extension was not present

UnexpectedStream

An unexpected stream type was received

BoundsExceeded(BoundsExceeded)

An integer was too large for the QUIC varint range.

Duplicate

A duplicate ID was used

Cancel

Nobody is reading any more, so the producer stopped. Not a failure.

Timeout

It took too long to open or transmit a stream.

Old

The group is older than the latest group and dropped.

App(u16)

An application-chosen close code. Bounded to u16 and offset past the library’s reserved range (+ 64) on the wire by Self::to_code, so app codes never collide with protocol ones.

The width asymmetry with Self::Remote is deliberate: App is a code this side chooses to send, while Remote carries a raw code received off the wire that didn’t map to a known variant, which can be any u32.

NotFound

The requested broadcast or track does not exist at the peer.

Unroutable

A broadcast was requested that is neither announced nor served by a dynamic router, so there is no route to it.

WrongSize

A frame’s payload length disagreed with its declared size.

ProtocolViolation

The peer broke a protocol rule; the session is unusable.

Unauthorized

The peer’s token does not grant the requested path or operation.

UnexpectedMessage

A valid message arrived in a state where it is not allowed.

Unsupported

The peer asked for a feature this endpoint does not implement.

Encode(EncodeError)

A message could not be serialized for the negotiated version.

TooManyParameters

A message carried more parameters than this endpoint accepts.

InvalidRole

The peer acted against the Role it advertised at SETUP.

UnknownAlpn(String)

The peer offered an ALPN this endpoint doesn’t recognize, so no version could be negotiated. A connect-time error.

Dropped

The producer was dropped without finishing, so the content is incomplete.

Closed

The handle was already closed by this side.

Lagged

The reader fell behind the group’s byte budget: the frame it wanted was dropped to keep the group under its size limit. Named from the consumer’s side (nothing is “full”); distinct from Self::Evicted, which drops a whole group under the pool’s memory pressure.

FrameTooLarge

A frame declared a payload size larger than the receiver accepts.

TimestampMismatch

A frame’s timestamp doesn’t match its track’s negotiated timescale: it’s missing on a timed track, present on an untimed track, or carries a different scale than the track advertised.

Evicted

The group was evicted from the cache under memory pressure (see cache::Pool). Unlike Self::Old, the group was still within the publisher’s window; it can be re-fetched.

Remote(u32)

A remote error received via a stream/session reset code.

Implementations

impl Error

pub fn to_code(&self) -> u32

An integer code that is sent over the wire.

pub fn from_transport(err: impl Error) -> Self

Convert a transport error into an Error, decoding stream reset codes.

Trait Implementations

impl Clone for Error

fn clone(&self) -> Error

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl Error for Error

fn session_error(&self) -> Option<(u32, String)>

Returns the error code and reason if this was an application error.

fn stream_error(&self) -> Option<u32>

Returns the error code if this was a stream error.

impl From<BoundsExceeded> for Error

fn from(source: BoundsExceeded) -> Self

Converts to this type from the input type.

impl From<DecodeError> for Error

fn from(source: DecodeError) -> Self

Converts to this type from the input type.

impl From<EncodeError> for Error

fn from(source: EncodeError) -> Self

Converts to this type from the input type.