rb: Add debug logger message for processing frames


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@669037 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/rb/lib/thrift/server/nonblockingserver.rb b/lib/rb/lib/thrift/server/nonblockingserver.rb
index 7868bab..70a58b5 100644
--- a/lib/rb/lib/thrift/server/nonblockingserver.rb
+++ b/lib/rb/lib/thrift/server/nonblockingserver.rb
@@ -139,6 +139,7 @@
         @buffers[fd] << fd.readpartial(1048576)
         frame = slice_frame!(@buffers[fd])
         if frame
+          @logger.debug "#{self} is processing a frame"
           @worker_queue.push [:frame, fd, frame]
         end
       end