Optimize transferring small objects for storage

[hekaisheng]

What do these changes do?

Related issue number

This PR implements a method that send small objects directly to receiver without split them into small blocks.

Fixes #xxxx

Check code requirements

• tests added / passed (if needed)
• Ensure all linting tests pass, see here for how to run them

[qinxuye]

Seems vineyard cannot pass the ut for this PR, @sighingnow do you have to time to help to see what's going on?

[sighingnow]

Seems vineyard cannot pass the ut for this PR, @sighingnow do you have to time to help to see what's going on?

I would take a look later today.

[sighingnow]

Seems vineyard cannot pass the ut for this PR, @sighingnow do you have to time to help to see what's going on?

I would take a look later today.

Sorry for the delay... Will be fixed today.

[sighingnow]

I failed to reproduce the failure if only run the single test case. But I found the test case test_execute_describe failed both for default storage and vineyard storage under this PR.

I have tried to debugging but failed to address the root cause. I think it is not a vineyard-only issue, @hekaisheng could you please help to try the test_execute_describe in your environment?

You could update the params to test the default storage only. The failre could be reproduced by

pytest -s -vvv mars/deploy/oscar/tests/test_local.py -k test_execute_describe