See if files can be held open as references.

[JakeRoggenbuck]

A lot of the read int and read string, which make up a large part of the daemon update call is spent opening and closing files often.
This time can be seen in read_int in green.

Here is how much of update read_int and read_str account for.

If we saved the files opened as refs, we could remove all of the open/close (blue) blocks in the update (green).