Imports cloud.google.com/go/storage github.com/Azure/azure-sdk-for-go/storage github.com/aws/aws-sdk-go/aws github.com/aws/aws-sdk-go/aws/awserr github.com/aws/aws-sdk-go/service/s3 github.com/aws/aws-sdk-go/service/s3/s3iface Standard library imports context errors fmt io path path/filepath time