[java-storage-nio] Support for START_OFF_SET and END_OFF_SET

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**Is your feature request related to a problem? Please describe.**
What the problem is. Example: I'm always frustrated when [...]
I am writing integration testing using FakeStorageRpc however my tests require using START_OFF_SET and END_OFF_SET.

**Describe the solution you'd like**
What you want to happen.
I would like to use FakeStorageRpc with START_OFF_SET and END_OFF_SET.

**Describe alternatives you've considered**
Any alternative solutions or features you've considered.
NA

**Additional context**
Any other context or screenshots about the feature request.