For Get:

• If the mapper returns a URL:
  • retrieve the URL contents into a file
  • return the path to the file.

This will be optimized in subsequent stories by "add read support for various transports to the afw object readers". This is a degenerate case that will be used if the object does not have a reader for a given transport protocol.

Need to solve the cleanup problem of when to delete the file that was downloaded.

For Put:

• serialize the object to a temporary file
• transfer the file to the URL