Improved handling of idle sessions by AbstractIOSessionPool / H2ConnPool

[ok2c]

@arturobernalg you have been working a lot with the connection pools. Could you please double-check my changes to make sure we are on the same page as far as idle connection handling is concerned?

[arturobernalg]

@ok2c IOSession#getLastEventTime() is based on System.nanoTime(), while inactivityDeadline() is based on Clock#millis() converted to nanoseconds. These use different time origins, so I don't think they can be compared directly. Am I missing something?

[ok2c]

@arturobernalg I suspected something was off. I misunderstood how System.nanoTime() worked. Now I think we have a problem. Why did we need to convert the i/o reactor timestamps to using System.nanoTime()? What was the point? I will start a discussion on the dev list.