foldAsync
Just like fold but receives a function that results in a Future CompletionStage to the next value.
Signature
Source.foldAsyncSource.foldAsync Flow.foldAsyncFlow.foldAsync
Description
Just like fold but receives a function that results in a Future CompletionStage to the next value.
Note that the zero value must be immutable.
Reactive Streams semantics
emits when upstream completes and the last Future CompletionStage is resolved
backpressures when downstream backpressures
completes when upstream completes and the last Future CompletionStage is resolved