Enum Error 

#[non_exhaustive]
pub enum Error {
    Engine(Error),
    ThreadNotStarted {
        reason: String,
    },
    HostStopped,
    ResultLost,
    Payload(Error),
    Transport(Error),
    ControlFrameTooLarge {
        bytes: usize,
        limit: usize,
    },
}

A failure from the host, as distinct from a failure from the engine.

The two are worth telling apart. An Engine error means the engine refused the work and the host is still serving; the other variants mean the host itself is unavailable, and retrying the same request will not help.

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.

Engine(Error)

The engine refused the work. The host is unaffected.

ThreadNotStarted

The engine thread could not be started.

Fields

reason: String

What the operating system reported.

HostStopped

The engine thread has stopped, so no further work can be run.

Terminal for this host: build a new one.

ResultLost

The work was submitted but the thread ended before answering.

Payload(Error)

A message’s object payload could not be turned into data.

Separate from Engine because the engine answered perfectly well: what failed was rendering the tree it handed over, and the rest of the message is still worth delivering.

Transport(Error)

The socket carrying events failed.

Separate again from Engine: the engine is fine and the run is unaffected, only the listener is unreachable. A host may well choose to keep testing and stop reporting.

ControlFrameTooLarge

A control frame payload exceeded what the protocol allows.

RFC 6455 section 5.5 caps every control frame at 125 bytes. A peer that receives a larger one fails the connection, and the send that caused it reports success, so this is raised before the frame goes out.

Fields

bytes: usize

What was offered.

limit: usize

What the protocol allows.

Trait Implementations

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 From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.