Reads from the channel (pipe) that is the output pipe for a
        called Popen. As we are reading from the pipe, the output is added
        to a deque. After the size of the deque exceeds the sizelimit
        earlier (older) entries are removed.

        This means the returned output is chunksize-sensitive, but is not
        really byte-sensitive.

def run(self):
        '''Reads from the channel (pipe) that is the output pipe for a
        called Popen. As we are reading from the pipe, the output is added
        to a deque. After the size of the deque exceeds the sizelimit
        earlier (older) entries are removed.

        This means the returned output is chunksize-sensitive, but is not
        really byte-sensitive.
        '''
        try:
            while True:
                line = self.chan.read(self.chunksize)
                if not line:
                    # Pipe can remain open after output has completed
                    break
                self.deque.append(line)
        except (ValueError, IOError):
            # pipe has closed, meaning command output is done
            pass
        self.running = False