RE: libpq debug log

Hi,

I have developed a new libpq trace logging aimed at checking which side (server or client) is causing the performance
issue.

The new libpq trace log can do the following things;
- Setting whether to get log or not by using connection strings or environment variables. It means that application
sourcecode changes is not needed to get the log.
 
- Getting time when receive and send process start/end. Functions too.
- Setting log level; When level1(default) is set, it outputs the time in the function and connection time. When level2
isset, it outputs information on the protocol message being exchanged, in addition to level1 information.
 

I updated patch, but I am not sure if these changes and implementation are correct or not. So I need your comment and
advice.
I would appreciate your advice and develop/fix my patch further.

Regards,
Aya Iwata