pub enum Either<A, B> {
    Left(A),
    Right(B),
}
Expand description

Combines two different futures, streams, or sinks having the same associated types into a single type.

This is useful when conditionally choosing between two distinct future types:

use futures::future::Either;

let cond = true;

let fut = if cond {
    Either::Left(async move { 12 })
} else {
    Either::Right(async move { 44 })
};

assert_eq!(fut.await, 12);

Variants

Left(A)

First branch of the type

Right(B)

Second branch of the type

Implementations

Factor out a homogeneous type from an either of pairs.

Here, the homogeneous type is the first element of the pairs.

Factor out a homogeneous type from an either of pairs.

Here, the homogeneous type is the second element of the pairs.

Extract the value of an either over two equivalent types.

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Returns true if the underlying future should no longer be polled.

Returns true if the stream should no longer be polled.

The type of value produced on completion.

Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available. Read more

Values yielded by the stream.

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted. Read more

Returns the bounds on the remaining length of the stream. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The output that the future will produce on completion.

Which kind of future are we turning this into?

Creates a future from a value. Read more

The resulting type after obtaining ownership.

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

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

The type returned in the event of a conversion error.

Performs the conversion.

The type of successful values yielded by this future

The type of failures yielded by this future

Poll this TryFuture as if it were a Future. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type of successful values yielded by this future

The type of failures yielded by this future

Poll this TryStream as if it were a Stream. Read more