Merge multiple sources.
def merge[U >: Out, M](that: Graph[SourceShape[U], M], eagerComplete: Boolean = false): Repr[U] def mergeMat[U >: Out, Mat2, Mat3](that: Graph[SourceShape[U], Mat2], eagerComplete: Boolean = false)(matF: (Mat, Mat2) ⇒ Mat3): ReprMat[U, Mat3]
Merge multiple sources. Picks elements randomly if all sources has elements ready.
emits when one of the inputs has an element available
backpressures when downstream backpressures
completes when all upstreams complete (This behavior is changeable to completing when any upstream completes by setting