Struct tower::buffer::BufferLayer
source · [−]pub struct BufferLayer<Request> { /* private fields */ }
Expand description
Adds an mpsc buffer in front of an inner service.
The default Tokio executor is used to run the given service, which means that this layer can only be used on the Tokio runtime.
See the module documentation for more details.
Implementations
sourceimpl<Request> BufferLayer<Request>
impl<Request> BufferLayer<Request>
sourcepub fn new(bound: usize) -> Self
pub fn new(bound: usize) -> Self
Creates a new BufferLayer
with the provided bound
.
bound
gives the maximal number of requests that can be queued for the service before
backpressure is applied to callers.
A note on choosing a bound
When Buffer
’s implementation of poll_ready
returns Poll::Ready
, it reserves a
slot in the channel for the forthcoming call
. However, if this call doesn’t arrive,
this reserved slot may be held up for a long time. As a result, it’s advisable to set
bound
to be at least the maximum number of concurrent requests the Buffer
will see.
If you do not, all the slots in the buffer may be held up by futures that have just called
poll_ready
but will not issue a call
, which prevents other senders from issuing new
requests.