How to read all the data of unknown length from a StreamSocket in WinRT using DataReader

Question

I have configured my socket to read partial data too like this:

@socket = new Windows.Networking.Sockets.StreamSocket()
hostName = new Windows.Networking.HostName(@ip)
@ensureConnection = @socket.connectAsync(hostName, @port.toString())
.then () =>
  @writer = new DataWriter(@socket.outputStream)
  @reader = new DataReader(@socket.inputStream)
  @reader.inputStreamOptions = InputStreamOptions.partial

Then my function to read from the socket looks like this:

readLineAsync = (reader, buffer = "") ->
while reader.unconsumedBufferLength
  byte = reader.readByte()
  if byte is 0
    return WinJS.Promise.as(buffer)
  buffer += String.fromCharCode(byte)
reader.loadAsync(1024).then (readBytes) ->
  if readBytes is 0
    WinJS.Promise.as(buffer)
  else
    while reader.unconsumedBufferLength
      byte = reader.readByte()
      if byte is 0
        return WinJS.Promise.as(buffer)
      buffer += String.fromCharCode(byte)
    readLineAsync(reader, buffer)

There are 2 problems with this function:

1. With very large responses, the stack builds up with recursive readLineAsync calls. How can I prevent that? Should I use the WinJS Scheduler API or similar to queue the next call to readLineAsync?

2. Sometimes the reader.loadAsync does not finish when no data is on the socket anymore. Sometimes it does and readByte is 0 then. Why is that?

Why do I loop over the reader's uncunsumedBufferLength on 2 locations in that function? I initially had this code in the loadAsync continuation handler. But since a response can contain a terminating \0 char I need to check for unread data in the readers buffer upon function entry too.

Thats the pseudo loop to send/receive to/from the socket:

readResponseAsync = (reader) ->
  return readLineAsync(@reader).then (line) ->
    result = parseLine(line)
    if result.unknown then return readResponseAsync(reader)
    return result

@ensureConnection.then () =>
  sendCommand(...)

  readResponseAsync(@reader).then (response) ->
    # handle response

All the WinRT samples from MS deal with known amount of data on the socket, so they not really fit my scenario.