if (mClosed) { return; }  unregisterReadInterest();
        public void close() throws IOException {            synchronized (mLock) {                if (mClosed) {                    return;                }                                unregisterReadInterest();                                mCloseAfterWrite = true;                                if (!mWriteManager.isWritePending()) {                    cleanupChannel(CleanupReason.NORMAL);                }            }        }