Inject DbExecutor as an ExecutorService
TransportKeyManager needs to submit database tasks and wait for them to complete, so it needs to see the DbExecutor as an ExecutorService rather than an Executor.
Subtask of #111 (closed).
TransportKeyManager needs to submit database tasks and wait for them to complete, so it needs to see the DbExecutor as an ExecutorService rather than an Executor.
Subtask of #111 (closed).