Class to manage the HTTP message headers and body content, which could be anything at this point
This class should be extended by HttpMessageRequest and HttpMessageResponse classes and never used directly
ProxyStatistics object is used to track statistics collected during the proxy execution to report to the user via an HTTP request directed to the proxy itself, rather than meant for a remote host or port
Fill the given buffer with some bytes and return the number of bytes
added in the buffer.
This method may return immediately with nothing added in the buffer.