Unify DefaultBlockWorkerClient with AbstractClient

[YangchenYe323]

What changes are proposed in this pull request?

Make DefaultBlockWorkerClient extends from AbstractClient

Why are the changes needed?

• Address a todo issue in the codebase
• Reduce duplicated code
• Avoid doing the expensive connection when DefaultBlockWorkerClient is constructed, take advantage of the lazy connection mechanism of AbstractClient
• Improve the flexibility of AbstractClient

Does this PR introduce any user facing changes?

No

[YangchenYe323]

In order for DefaultBlockWorkerClient to inherit from AbstractClient, three issues have to be addressed:

1. DefaultBlockWorkerClient might not work with an InetSocketAddress as it might use a domain socket instead. Therefore, AbstractClient is modified to expose a getGrpcServerAddress method used to return whatever server address the client connects to. DefaultBlockWorkerClient overrides this method to return the address it needs for connection.

2. AbstractClient now can be extended to construct multiple channels corresponding to different GrpcNetworkGroup, so that DefaultBlockWorker can construct two channels, one for streaming and one for normal rpc, for its use.

3. AbstractClient currently hardcoded a version checking method, which alluxio workers don't hold. Therefore, a switch is exposed to control whether version checking should be run so that DefaultBlockWorkerClient can switch it off.

[YangchenYe323]

@beinan @dbw9580 Do you mind taking a look at this refactor? Thanks a lot!

[YangchenYe323]

@dbw9580 Cleaned up a bit and addressed your concerns. Would you like to take another look? Thanks!

[dbw9580]

Please try your best to preserve the behavior of the client, since this is a fundamental class, a lot of things depend on it.

[yyongycy]

What tests have been done? How do you make sure not to break some conner cases?

[YangchenYe323]

What tests have been done? How do you make sure not to break some conner cases?

Every test case that reads or writes from alluxio uses this class. Also tested the generated tarball against tests in ClientIO cluster.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in two weeks if no further activity occurs. Thank you for your contributions.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in two weeks if no further activity occurs. Thank you for your contributions.