Limit the maximum numbers of open sockets

[mcollina]

One of the first issues with "fetch failed" is that we don't limit the number of outgoing sockets, and the process runs out of them, triggering a timeout error.

I think we should add a limit of 127 per pool by default (or any other magic number)

[metcoder95]

The global dispatcher or the overall default Client/Agent settings?

[mcollina]

Both are good ideas.