This servlet is used to Proxy a Servlet request to another server for
processing and returns that result to the caller as if this Servlet actiually
serviced it.
This servlet is used to filter Servlet requests coming from another server
for processing and sets authentication for the user passed in by the
parameter _TRUST_USER_.
Example filter that sets the character encoding to be used in parsing the
incoming request, either unconditionally or only if the client did not
specify a character encoding.