Type Definition tracing_subscriber::fmt::writer::OptionalWriter [−][src]
pub type OptionalWriter<T> = EitherWriter<T, Sink>;
This is supported on crate feature
fmt
only.Expand description
A writer which may or may not be enabled.
This may be used by MakeWriter
implementations that wish to
conditionally enable or disable the returned writer based on a span or
event’s Metadata
.
Implementations
Returns a disabled writer.
Any bytes written to the returned writer are discarded.
This is equivalent to returning Option::None
.
Returns an enabled writer of type T
.
This is equivalent to returning Option::Some
.