+ """Create a new peer if necessary and forward the request to it.
+
+ @type site: (C{string}, C{int})
+ @param site: the IP address and port of the peer
+ @type path: C{string}
+ @param path: the path to the file on the peer
+ @type method: C{string}
+ @param method: the HTTP method to use, 'GET' or 'HEAD'
+ (optional, defaults to 'GET')
+ @type modtime: C{int}
+ @param modtime: the modification time to use for an 'If-Modified-Since'
+ header, as seconds since the epoch
+ (optional, defaults to not sending that header)
+ """