@Override
    public void write(int b) throws IOException {
        getOutputStream().write(b);
        bytesWritten++;
    }
Output stream that writes a lock file with the data and then renames to the
final file once closed.
<p>
If lazy is set on it also does not create the file until some data is written
(thus the file does not exist if no data was written).
stroom-data/stroom-data-store-impl-fs/src/main/java/stroom/data/store/impl/fs/LockingFileOutputStream.java