feature/issue-175-chunk-by-size

[njlr]

Adds chunkBySize and tests

Closes chunkBySize

[njlr]

Provided by bufferByCount

FSharp.Control.AsyncSeq/src/FSharp.Control.AsyncSeq/AsyncSeq.fs

Lines 1547 to 1562 in 4bdcf15

	let bufferByCount (bufferSize:int) (source:AsyncSeq<'T>) : AsyncSeq<'T[]> =
	if (bufferSize < 1) then invalidArg "bufferSize" "must be positive"
	asyncSeq {
	let buffer = new ResizeArray<_>()
	use ie = source.GetEnumerator()
	let! move = ie.MoveNext()
	let b = ref move
	while b.Value.IsSome do
	buffer.Add b.Value.Value
	if buffer.Count = bufferSize then
	yield buffer.ToArray()
	buffer.Clear()
	let! moven = ie.MoveNext()
	b := moven
	if (buffer.Count > 0) then
	yield buffer.ToArray() }