log file is created later than it should be

[cjMdGit]

Hi all,

I create a very simple logger which has an info stream and an error stream in a local utils.js, and include it into other js files. my node app is a http server that when a request comes in, it immediately sends a message into that logger. however I find that the log files are not created and able to save information when my server starts until a later time, so that the information on initial jobs is lost. Is there any clues  why this happens?  If I set the log files' type as rotating-file, they are created as expected.