Add buffer_queue_limit_log_level param to BasicBuffer.
buffer_queue_limit_log_level decides what happen when
the queue exceeds buffer_queue_limit.
If buffer_queue_limit_log_level is 'raise_exception':
  It raises BufferQueueLimitError.
  This is default behaviour.
If buffer_queue_limit_log_level is log level like 'info':
  It writes message to log file.
If buffer_queue_limit_log_level is 'off':
  It does nothing.