def fetch(self, request, callback, **kwargs):
if not isinstance(request, HTTPRequest):
request = HTTPRequest(url=request, **kwargs)
if not isinstance(request.headers, HTTPHeaders):
request.headers = HTTPHeaders(request.headers)
callback = stack_context.wrap(callback)
self.queue.append((request, callback))
self._process_queue()
if self.queue:
logging.debug("max_clients limit reached, request queued. "
"%d active, %d queued requests." %
(len(self.active), len(self.queue)))
