code: function (logInst) {
  
  	var log_id = logInst.id;
  
  	// create index to buffer map, if not exist
  	if (l_logBufferIdxByID.hasOwnProperty(log_id) === false)
  		l_logBufferIdxByID[log_id] = [];
  
  	l_logBufferIdxByID[log_id].push(logInst);
  
  	l_logBuffer.enqueue(logInst,
  
  		// callback to write log
  		function (tmpLog) {
  
  			// show notice if queued log exceeds limit (once each time multiples of the limit is reached)
  			if ((l_logBuffer.getLength() > 0) && (l_logBuffer.getLength() % l_logBufferOverloadLimit === 0)) {
  				console.log(l_name + '::l_writeLog::' + SR.Tags.YELLOW + 'log len=' + l_logBuffer.getLength() + SR.Tags.ERREND);
  			}
  
  			// lock individual log instance            
  			if (l_logs.hasOwnProperty(tmpLog.id) === true) {
  				// if we're busy writing now, wait till next time
  				if (l_logs[tmpLog.id].writing === true)
  					return false;
  
  				// lock the writing for this id
  				l_logs[tmpLog.id].writing = true;
  
  				SR.fs.writeSync(tmpLog.fd, tmpLog.msg, undefined, undefined);
  
  				// remove a flag record from topmost
  				if (l_logBufferIdxByID.hasOwnProperty(tmpLog.id) === true)
  					l_logBufferIdxByID[tmpLog.id].shift();
  
  				l_logs[tmpLog.id].writing = false;
  			}
  
  			// NOTE: processing will pause here if id doesn't exist in l_logs
  			// TODO: right behavior?
  			return true;
  		}
  	);
  }
docs: local helper to store one log message (to be written later)