Method flush

java/org/apache/coyote/http2/Stream.java:1034–1069

(boolean block)

        }

        final boolean flush(boolean block) throws IOException {
            writeLock.lock();
            try {
                /*
                 * Need to ensure that there is exactly one call to flush even when there is no data to write. Too few
                 * calls (i.e. zero) and the end of stream message is not sent for a completed asynchronous write. Too
                 * many calls and the end of stream message is sent too soon and trailer headers are not sent.
                 */
                boolean dataInBuffer = buffer.position() > 0;
                boolean flushed = false;

                if (dataInBuffer) {
                    dataInBuffer = flush(false, block);
                    flushed = true;
                }

                if (dataInBuffer) {
                    dataLeft = true;
                } else {
                    if (writeBuffer.isEmpty()) {
                        // Both buffer and writeBuffer are empty.
                        if (flushed) {
                            dataLeft = false;
                        } else {
                            dataLeft = flush(false, block);
                        }
                    } else {
                        dataLeft = writeBuffer.write(this, block);
                    }
                }

                return dataLeft;
            } finally {
                writeLock.unlock();
            }
        }

        private boolean flush(boolean writeInProgress, boolean block) throws IOException {
            writeLock.lock();