Type Alias tracing_subscriber::fmt::writer::OptionalWriter

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pub type OptionalWriter<T> = EitherWriter<T, Sink>;
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.

Aliased Type§

enum OptionalWriter<T> {
    A(T),
    B(Sink),
}

Variants§

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A(T)

A writer of type A.

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B(Sink)

A writer of type B.

Implementations§

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impl<T> OptionalWriter<T>

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pub fn none() -> Self

Returns a disabled writer.

Any bytes written to the returned writer are discarded.

This is equivalent to returning Option::None.

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pub fn some(t: T) -> Self

Returns an enabled writer of type T.

This is equivalent to returning Option::Some.

Trait Implementations§

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impl<T> From<Option<T>> for OptionalWriter<T>

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fn from(opt: Option<T>) -> Self

Converts to this type from the input type.
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impl<A: Clone, B: Clone> Clone for EitherWriter<A, B>

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fn clone(&self) -> EitherWriter<A, B>

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<A: Debug, B: Debug> Debug for EitherWriter<A, B>

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

Formats the value using the given formatter. Read more
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impl<A: PartialEq, B: PartialEq> PartialEq for EitherWriter<A, B>

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fn eq(&self, other: &EitherWriter<A, B>) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<A, B> Write for EitherWriter<A, B>
where A: Write, B: Write,

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fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this writer, returning how many bytes were written. Read more
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fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
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fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>

Like write, except that it writes from a slice of buffers. Read more
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fn write_all(&mut self, buf: &[u8]) -> Result<()>

Attempts to write an entire buffer into this writer. Read more
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fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<()>

Writes a formatted string into this writer, returning any error encountered. Read more
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fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector #69941)
Determines if this Writer has an efficient write_vectored implementation. Read more
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fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored #70436)
Attempts to write multiple buffers into this writer. Read more
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fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Creates a “by reference” adapter for this instance of Write. Read more
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impl<A: Copy, B: Copy> Copy for EitherWriter<A, B>

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impl<A: Eq, B: Eq> Eq for EitherWriter<A, B>

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impl<A, B> StructuralPartialEq for EitherWriter<A, B>