F# websocket work-in-progress

websockets.fs

type WebSocketResponse =
    | Close
    | Message of msg : string

let rec readMessagePatternMatch (ws:WebSocket) : Async<WebSocketResponse> =
    let buffer : byte array = Array.zeroCreate 1024
    let utf8 = new UTF8Encoding()
    async {
        let! payload = ws.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None) |> Async.AwaitTask
        return! match payload.MessageType with
                     | WebSocketMessageType.Binary -> async.Return (failwith "unsupported binary message")
                     | WebSocketMessageType.Close -> async.Return WebSocketResponse.Close
                     | WebSocketMessageType.Text -> 
                            let content = utf8.GetString(buffer)
                            if payload.EndOfMessage then
                                async.Return (WebSocketResponse.Message(content))
                            else
                                async {
                                    let! next = readMessage ws
                                    return match next with
                                            | WebSocketResponse.Message(nextmsg) -> WebSocketResponse.Message(content + nextmsg)
                                            | other -> other
                                }
                     | _ -> failwith "unexpected enum value"
    }

let rec readMessageIfElse (ws:WebSocket) : Async<WebSocketResponse> =
    let buffer : byte array = Array.zeroCreate 1024
    let utf8 = new UTF8Encoding()
    async {
        let! payload = ws.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None) |> Async.AwaitTask
        if payload.MessageType = WebSocketMessageType.Binary then
            return failwith "unsupported binary message"
        else if payload.MessageType = WebSocketMessageType.Close then
            return WebSocketResponse.Close
        else // if payload.MessageType = WebSocketMessageType.Text then
            let content = utf8.GetString(buffer)
            if payload.EndOfMessage then
                return WebSocketResponse.Message(content)
            else
                let! successor = readMessage ws
                return match successor with
                       | WebSocketResponse.Message(msg) -> WebSocketResponse.Message(content + msg)
                       | other -> other
    }