presto-main/src/main/java/io/prestosql/execution/buffer/LazyOutputBuffer.java/LazyOutputBuffer/abort
class LazyOutputBuffer:    @Override
    public void abort(OutputBufferId bufferId)
    {
        OutputBuffer outputBuffer;
        synchronized (this) {
            if (delegate == null) {
                abortedBuffers.add(bufferId);
                // Normally, we should free any pending readers for this buffer,
                // but we assume that the real buffer will be created quickly.
                return;
            }
            outputBuffer = delegate;
        }
        outputBuffer.abort(bufferId);
    }