code: function respond(options, content, cache) {
  				// cache the response
  
  				var cached = that.responseCache.set(state, queryId, options, cache);
  
  				// send the response back to the client
  
  				cb(null, content, options);
  
  				// log the execution time
  
  				var msg = cached ?
  					'Executed and cached user command batch' :
  					'Executed user command batch (could not cache)';
  
  				logger.debug
  					.data({
  						batch: batch.commandNames,
  						queryId: queryId,
  						durationMsec: duration(),
  						options: options,
  						dataSize: content.length
  					})
  					.log(msg);
  			}
docs: start executing commands and build a serialized output response