private void release() {
        isAvailableForWriting = true;
        if (pooledByteBuffer != null) {
            LOGGER.trace("Releasing pooledBuffer {}", pooledByteBuffer);
            pooledByteBuffer.close();
            pooledByteBuffer = null;
        }
    }
Release the underlying {@link ByteBuffer} back to the pool. Once released,
the {@link ByteBuffer} cannot be used any more and you should not retain any
references to it. Identical behaviour to calling {@link PooledByteBufferOutputStream#close()}.
stroom-bytebuffer/src/main/java/stroom/bytebuffer/PooledByteBufferOutputStream.java