This is a custom build of Vapor's Websocket Kit. Following changes are made:

• BufferWritableMonitorDelegate: a delegate that receives the amount of buffered bytes from the channel. This is not the actual representation of buffered bytes in the channel, but more of an estimate.
• BufferWritableMonitorHandler: a channel duplexer that handles buffering and report the buffered amount to the delegate.
• writeBufferWaterMark: the water mark that defines the amount of bytes that will be buffered in the channel.
• WebSocketClient, WebSocket that uses the aforementioned utilities.