iter_bucket - client args enhancement

[govindmurthi21]

Hello. Will it be possible for you to add the ability to pass in the client args into the method s3.iter_bucket. This will allow us to read from other sources such as Dell ECS.

Currently the s3.iter_bucket method accepts the following args
bucket_name,
prefix='',
accept_key=None,
key_limit=None,
workers=16,
retries=3,
**session_kwargs

If we can add passing in the client args - such as listed here https://boto3.amazonaws.com/v1/documentation/api/latest/reference/core/session.html#boto3.session.Session.client
and pass that into the list_buckets method that will help me with my current problem of reading files from Dell EMC ECS and uploading the same to AWS S3