* TODO Rename Ext,Extension -> Cap
* TODO Use System.IO instead of Network.recv/send
  The functions in System.IO use GHC/base's built in support for epoll/kqueue
  and the like which makes them a whole lot more efficient for file descriptor
  I/O. Network.recv/send on the other hand just use a plain FFI call to
  recvmsg/sendmsg which will block the whole OS thread.

** TODO Compare performance of the two
* TODO Proper handling of transaction ids in UDP tracker

Just like the krpc package does.