library/src/main/java/com/liulishuo/filedownloader/util/FileDownloadSerialQueue.java
public void pause() {
        synchronized (finishCallback) {
            if (paused) {
                FileDownloadLog.w(this, "require pause this queue(remain %d), but "
                        + "it has already been paused", mTasks.size());
                return;
            }

            paused = true;
            mTasks.drainTo(pausedList);
            if (workingTask != null) {
                workingTask.removeFinishListener(finishCallback);
                workingTask.pause();
            }
        }

    }
public void pause() {
        synchronized (finishCallback) {
            if (paused) {
                FileDownloadLog.w(this, "require pause this queue(remain %d), but "
                        + "it has already been paused", mTasks.size());
                return;
            }

            paused = true;
            mTasks.drainTo(pausedList);
            if (workingTask != null) {
                workingTask.removeFinishListener(finishCallback);
                workingTask.pause();
            }
        }

    }
Pause the queue.

@see #resume()