While this might help for deltas, the SDK should be returning metrics every single collection for readers that are CUMULATIVE (the default). However that seems to not be working corrctly https://github.com/open-telemetry/opentelemetry-python/issues/3277#issuecomment-1684521139

Yes, noticed that now that I added another test case. I think this is a problem for the explicit bucket histogram aggregation who is resetting to zero all bucket counts after every collection even in the aggregation temporality is cumulative. I say we review this PR and address that issue separately.

Originally posted by @aabmass in #3335 (review)