[Freeswitch-dev] mod_fifo.c question re: fifo count values

I was curious about this code snippet which appears in mod_fifo.c near line 3775 and again near line 3786: len = node_caller_count(node); switch_mutex_lock(node->update_mutex); stream->write_function(stream, "%s:%d:%d:%d\n", argv[1], node->consumer_count, node_caller_count(node), len); switch_mutex_unlock(node->update_mutex); I was curious: what's the difference in the stream->write between node_caller_count(node) and len? Under what circumstances would they be different? (I'm assuming the locking of the mutex after setting the value of len may have something to do with it...) Thanks, MC