The desiredSize
read-only property of the ReadableByteStreamController
interface returns the number of bytes required to fill the stream's internal queue to its "desired size".
The value is used by the stream to indicate a preferred flow rate to the underlying source. Sources that support throttling or pausing their inflow of data (not all do!) should control the inflow such that desiredSize
of the stream buffer is kept positive and as close to zero as possible.
The desiredSize
is used to apply backpressure from downstream consumers.