syleshfb

Dynamic bucket creation customization options

2

**What does this PR do? Please describe:** Add a new optional argument to dynamic_bucket---bucket_creation_fn---to allow the user to customize how buckets are created. bucket_creation_fn allows the user to customize what...

**What does this PR do? Please describe:** Adds a utility function, read_and_pickle_wrap_iterator, to which any iterator/generator can be passed. This will wrap the iterator/generator in a class whose pickle behavior...