socketMap is not cleaned on unregister

[agising]

When unregistering from poller the socketMap dict is not updated. When registering again the poller somtimes get out of index.
Suggested solution, clear dict entry in poller:

        public func unregister(socket: Socket) throws {
            let socketIndex = socketMap[socket]!
            sockets.remove(at: socketIndex)
            socketMap[socket] = nil

            // Update indices of all other sockets in the socket map
            for (socket, _) in sockets.suffix(from: socketIndex) {
                let socketIndex = socketMap[socket]!
                socketMap[socket] = socketIndex - 1
            }
        }

Edit: formatting