In internal proc, set datatypes_callback. This will allow media files coming from tensorboard to sync while the run is still running.

[coveralls]

Pull Request Test Coverage Report for Build dc41d15d-5b75-48da-b3f4-da61c478a873

• 2 of 8 (25.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.009%) to 61.017%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
wandb/internal/run.py	1	2	50.0%
wandb/internal/tb_watcher.py	1	6	16.67%
<!--	Total:	2	8	25.0%	-->

Totals
Change from base Build a4ccfcdd-b322-4df6-8599-3ed2ce1d9452:	-0.009%
Covered Lines:	12935
Relevant Lines:	21199

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💛 - Coveralls