Support for assume role while using ec2instancemetadata

[orderedchaosdev]

Is your feature request related to a problem? Please describe.
On my ec2 instances I shouldn't need to have an aws access key just to assume a role since that defeats the added value of having iam roles.

Describe the solution you'd like
I would like to be able to assume a role using ec2 instances metadata credentials just like you can normally with profiles and the aws cli

Describe alternatives you've considered
Configure cross account permissions to allow the iam instance role to access the s3 buckets without assuming roles.

Additional context