prevent busy looping

lib/interface.py

@@ -257,10 +257,15 @@ class Interface(util.PrintError):
         self.request_time = time.time()
         self.unsent_requests.append(args)
 
+    def num_requests(self):
+        '''Keep unanswered requests below 100'''
+        n = 100 - len(self.unanswered_requests)
+        return min(n, len(self.unsent_requests))
+
     def send_requests(self):
         '''Sends queued requests.  Returns False on failure.'''
         make_dict = lambda (m, p, i): {'method': m, 'params': p, 'id': i}
-        n = 100 - len(self.unanswered_requests)
+        n = self.num_requests()
         wire_requests = self.unsent_requests[0:n]
         try:
             self.pipe.send_all(map(make_dict, wire_requests))