# tracing::dispatcher::Dispatch - Rust
API documentation for the Rust `Dispatch` struct in crate `tracing`.
Keywords: rust, rustlang, rust-lang, Dispatch

# Struct tracing::dispatcher::Dispatch [−] [src]

    pub struct Dispatch { /* fields omitted */ }

`Dispatch` trace data to a `Subscriber`.

## Implementations

### `impl Dispatch` [src]

#### `pub fn none() -> Dispatch` [src]

Returns a new `Dispatch` that discards events and spans.

#### `pub fn new<S>(subscriber: S) -> Dispatch where
S: Subscriber + Send + Sync + 'static,` [src]

Returns a `Dispatch` that forwards to the given `Subscriber`.

#### `pub fn register_callsite(
&self,
metadata: &'static Metadata<'static>
) -> Interest` [src]

Registers a new callsite with this subscriber, returning whether or not the subscriber is interested in being notified about the callsite.

This calls the `register_callsite` function on the `Subscriber` that this `Dispatch` forwards to.

#### `pub fn new_span(&self, span: &Attributes<'_>) -> Id` [src]

Record the construction of a new span, returning a new ID for the span being constructed.

This calls the `new_span` function on the `Subscriber` that this `Dispatch` forwards to.

#### `pub fn record(&self, span: &Id, values: &Record<'_>)` [src]

Record a set of values on a span.

This calls the `record` function on the `Subscriber` that this `Dispatch` forwards to.

#### `pub fn record_follows_from(&self, span: &Id, follows: &Id)` [src]

Adds an indication that `span` follows from the span with the id `follows`.

This calls the `record_follows_from` function on the `Subscriber` that this `Dispatch` forwards to.

#### `pub fn enabled(&self, metadata: &Metadata<'_>) -> bool` [src]

Returns true if a span with the specified metadata would be recorded.

This calls the `enabled` function on the `Subscriber` that this `Dispatch` forwards to.

#### `pub fn event(&self, event: &Event<'_>)` [src]

Records that an `Event` has occurred.

This calls the `event` function on the `Subscriber` that this `Dispatch` forwards to.

#### `pub fn enter(&self, span: &Id)` [src]

Records that a span has been can_enter.

This calls the `enter` function on the `Subscriber` that this `Dispatch` forwards to.

#### `pub fn exit(&self, span: &Id)` [src]

Records that a span has been exited.

This calls the `exit` function on the `Subscriber` that this `Dispatch` forwards to.

#### `pub fn clone_span(&self, id: &Id) -> Id` [src]

Notifies the subscriber that a span ID has been cloned.

This function must only be called with span IDs that were returned by this `Dispatch`'s `new_span` function. The `tracing` crate upholds this guarantee and any other libraries implementing instrumentation APIs must as well.

This calls the `clone_span` function on the `Subscriber` that this `Dispatch` forwards to.

#### `pub fn drop_span(&self, id: Id)` [src]

👎 Deprecated since 0.1.2:

use `Dispatch::try_close` instead

Notifies the subscriber that a span ID has been dropped.

This function must only be called with span IDs that were returned by this `Dispatch`'s `new_span` function. The `tracing` crate upholds this guarantee and any other libraries implementing instrumentation APIs must as well.

This calls the `drop_span` function on the `Subscriber` that this `Dispatch` forwards to.

⚠ ️Warning

    Deprecated: The try_close
    method is functionally identical, but returns true if the span is now closed.
    It should be used instead of this method.

#### `pub fn try_close(&self, id: Id) -> bool` [src]

Notifies the subscriber that a span ID has been dropped, and returns `true` if there are now 0 IDs referring to that span.

This function must only be called with span IDs that were returned by this `Dispatch`'s `new_span` function. The `tracing` crate upholds this guarantee and any other libraries implementing instrumentation APIs must as well.

This calls the `try_close` function on the `Subscriber` that this `Dispatch` forwards to.

#### `pub fn current_span(&self) -> Current` [src]

Returns a type representing this subscriber's view of the current span.

This calls the `current` function on the `Subscriber` that this `Dispatch` forwards to.

#### `pub fn is<T>(&self) -> bool where
T: Any,` [src]

Returns `true` if this `Dispatch` forwards to a `Subscriber` of type `T`.

#### `pub fn downcast_ref<T>(&self) -> Option<&T> where
T: Any,` [src]

Returns some reference to the `Subscriber` this `Dispatch` forwards to if it is of type `T`, or `None` if it isn't.

## Trait Implementations

### `impl Clone for Dispatch` [src]

#### `pub fn clone(&self) -> Dispatch` [src]

Returns a copy of the value. Read more

#### `pub fn clone_from(&mut self, source: &Self)`1.0.0 [src]

Performs copy-assignment from `source`. Read more

### `impl Debug for Dispatch` [src]

#### `pub fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>` [src]

Formats the value using the given formatter. Read more

### `impl Default for Dispatch` [src]

#### `pub fn default() -> Dispatch` [src]

Returns the current default dispatcher

### `impl<S> From<S> for Dispatch where
S: Subscriber + Send + Sync + 'static,` [src]

#### `pub fn from(subscriber: S) -> Dispatch` [src]

Performs the conversion.

## Auto Trait Implementations

### `impl !RefUnwindSafe for Dispatch` [src]

### `impl Send for Dispatch` [src]

### `impl Sync for Dispatch` [src]

### `impl Unpin for Dispatch` [src]

### `impl !UnwindSafe for Dispatch` [src]

## Blanket Implementations

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `pub fn type_id(&self) -> TypeId` [src]

Gets the `TypeId` of `self`. Read more

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow(&self) -> &T` [src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow_mut(&mut self) -> &mut T` [src]

Mutably borrows from an owned value. Read more

### `impl<T> From<T> for T` [src]

#### `pub fn from(t: T) -> T` [src]

Performs the conversion.

### `impl<T> Instrument for T` [src]

#### `fn instrument(self, span: Span) -> Instrumented<Self>ⓘ

### Notable traits for Instrumented<T>

`impl<T: Future> Future for Instrumented<T> type Output = T::Output;`
` [src]

Instruments this type with the provided `Span`, returning an `Instrumented` wrapper. Read more

#### `fn in_current_span(self) -> Instrumented<Self>ⓘ

### Notable traits for Instrumented<T>

`impl<T: Future> Future for Instrumented<T> type Output = T::Output;`
` [src]

Instruments this type with the current `Span`, returning an `Instrumented` wrapper. Read more

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `pub fn into(self) -> U` [src]

Performs the conversion.

### `impl<T> ToOwned for T where
T: Clone,` [src]

#### `type Owned = T`

The resulting type after obtaining ownership.

#### `pub fn to_owned(&self) -> T` [src]

Creates owned data from borrowed data, usually by cloning. Read more

#### `pub fn clone_into(&self, target: &mut T)` [src]

🔬 This is a nightly-only experimental API. (`toowned_clone_into` #41263)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>` [src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>` [src]

Performs the conversion.