Struct Subscriber 

pub struct Subscriber(/* private fields */);

A boxed Subscriber with a real Debug impl (the diagnostics matter; the subscriber’s innards do not).

Exists because hosts that assert on build_subscriber results need unwrap()/unwrap_err() ergonomics, which require the ok/error types to be Debug — a bare Box<dyn Subscriber> is not.

Trait Implementations

impl Debug for Subscriber

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

Formats the value using the given formatter.

impl Subscriber for Subscriber

fn enabled(&self, metadata: &Metadata<'_>) -> bool

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

fn new_span(&self, span: &Attributes<'_>) -> Id

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

fn record(&self, span: &Id, values: &Record<'_>)

Record a set of values on a span.

fn record_follows_from(&self, span: &Id, follows: &Id)

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

fn event(&self, event: &Event<'_>)

Records that an Event has occurred.

fn enter(&self, span: &Id)

Records that a span has been entered.

fn exit(&self, span: &Id)

Records that a span has been exited.

fn clone_span(&self, span: &Id) -> Id

Notifies the subscriber that a span ID has been cloned.

fn try_close(&self, id: Id) -> bool

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

fn current_span(&self) -> Current

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

fn max_level_hint(&self) -> Option<LevelFilter>

Returns the highest verbosity level that this Subscriber will enable, or None, if the subscriber does not implement level-based filtering or chooses not to implement this method.

fn on_register_dispatch(&self, subscriber: &Dispatch)

Invoked when this subscriber becomes a Dispatch.

fn register_callsite(&self, metadata: &'static Metadata<'static>) -> Interest

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

fn event_enabled(&self, event: &Event<'_>) -> bool

Determine if an Event should be recorded.

fn drop_span(&self, _id: Id)

👎Deprecated since 0.1.2:

use Subscriber::try_close instead

This method is deprecated.

unsafe fn downcast_raw(&self, id: TypeId) -> Option<*const ()>

If self is the same type as the provided TypeId, returns an untyped *const pointer to that type. Otherwise, returns None.