add agent.destroy

[vvo]

To close all remaining free sockets, thoughts @simov?

[simov]

Sounds logical, I guess you are referring to the code used in this test request/request#1511 (comment)

If you are going to implement that method here, we're also going to need a failing test in the request repository, as we don't have any tests here.

[andrew-aladev]

We've fixed this issue in this fork. Should we provide a pull request?

PS Original forever agent has an issue with.

  if (this.sockets[name]) {
    ...
  } else if (this.sockets[name] && this.sockets[name].length === 0) {
    ...
  }

else won't be invoked.