[feature] Allow easy measurement of handlers in a pipeline

[diwakergupta]

E.g. I want to spend how much time my application is spending in the SSLHandler. It is near impossible to do this today, apart from some clunky hacks that may end up polluting the measurements.

Copying relevant bits from IRC:

[11:40:57]  <diwaker>    trying to figure out the best way to measure the time spent in each of the handlers in my pipeline
[11:41:06]  <diwaker>    surely someone has written a handler decorator for this? :-)
[11:41:19]  <diwaker>    any suggestions on doing this the netty way are much appreciated!
[11:47:35]  <@normanm>   diwaker the problem is that each handler will call the next one
[11:48:39]  <diwaker>    right so a really crude way out be to insert dummy handlers before/after the handler I want
[11:48:47]  <diwaker>    and measure time in those
[11:49:15]  <diwaker>    I'm specifically interested in measuring the SSLHandler performance and don't see any existing hooks for that :/
[11:49:34]  <diwaker>    normanm: surely I'm not the only one who's wanted to do this? ;-)
[11:50:08]  <@normanm>   I think the right way would in DefaultChannelHandlerContext
[11:50:18]  <@normanm>   can you add a github issue ?

[WhiteTrashLord]

The performance of the Java based SSL Handler is bad. You should switch to native SSL solution.