// Marshal the XML-RPC request as a POST variable. <nil/> is an
// extension to the XML-RPC spec that is supported in our custom
// version of xmlrpc.so via the 'allow_null' output_encoding key.
// Marshal the XML-RPC request as a POST variable. <nil/> is an
// extension to the XML-RPC spec that is supported in our custom
// version of xmlrpc.so via the 'allow_null' output_encoding key.