Description of changes:

Before

• Setting predownload=0 results in indefinite hang.

After

• Change the logic of downloading samples to n + 1 samples as compared to n where n is the predownload value. Hence predownload=0 means that the streaming dataset downloads 1 sample at a time during each iter -> getitem call.
  - Consequences
  • Each worker downloads one extra sample before it waits for sample ahead check. I think downloading one extra sample won't have much impact on the dataset iter time.

Issue #, if available:

STR-121

Merge Checklist:

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