During ZIP Export, we use the archive's configured ExecutorService to submit the encoding task, letting the reader continue in the Main thread. This enables an encoding-on-demand which limits resource starvation (only encode as the archive is read) and keeps us from generating OOME as defined by SHRINKWRAP-137.

There's currently no mechanism to shut down the ES however, leaving non-daemon threads hanging around which prevent the JVM from shutting down. When the task is completed, ensure the service shuts down.