WebSocketHandler Module

# Introduction to the WebSocketHandler Module

The WebSocketHandler module provides a handler to be used with the HttpServer module to provide server-side RFC-6455 based WebSocket services to clients.

To use this module, use `"%requires WebSocketHandler"` and `"%requires HttpServer"` in your code.

All the public symbols in the module are defined in the WebSocketHandler namespace.

The main classes provided in this module are:

- WebSocketHandler::WebSocketConnection
- WebSocketHandler::WebSocketHandler

# WebSocketHandler Release History

## Version 1.5.2

- fixed a bug handling closing server-side web sockets on demand (issue 4075)
- fixed a bug where I/O could not be flushed before closing the socket (issue 4074)
- added support for continuation frames (issue 4073)

## Version 1.5.1

- fixed a bug handling the case when a connection object is deleted in a callback method (issue 4063)

## Version 1.5

- allow the WebSocket handler to have connections added to it from outside the class

## Version 1.4.3

- added missing exception handling to connection registration code (issue 3215)
- added WebSocketHandler::WebSocketConnection::stop() and WebSocketHandler::WebSocketHandler::stopOne()

## Version 1.4.2

- added support for heartbeat messages (issue 2887)

## Version 1.4.1

- fixed a bug where unsolicited `PONG` messages caused the connection to be prematurely closed (issue 2566)

## Version 1.4

- added support for complex types
- added the WebSocketHandler::WebSocketConnection::registered() method

## Version 1.3

- added timeout values to Socket calls (issue 1725)

## Version 1.2

- fixed a bug parsing and generating the websocket close status code (issue 1216)

## Version 1.1

- bug fix: do not delete the connection object when the connection closes, remove it so it can go out of scope naturally to avoid excess exceptions in the server code
- added the WebSocketConnection::connectionClosed() method which is called when the connection is closed

## Version 1.0

- the initial version of the WebSocketHandler module