JVM Hangs on gRPC if you don't close Spanner Object #2315

I ran across a path with the Java Spanner client that if you create several Spanner instances and do not explicitly close them the JVM will hang (it will not terminate it's process after code execution).

To reproduce the behavior create an object that wraps Spanner creation. Create the object several times in a loop. Then execute some additional code.

You can see the hanging wait on KQueueArrayWrapper.

Thanks.