We can improve our test story for tiered storage.  First, we have the ability in dir_store to specify configuration to add delays for simulated network operations.  But hook_tiered and helper_tiered don't make this easy to get to.

Second, once we have the above, we should have a variant of the hook tiered evergreen tests to exercise tests with some delays.

Third, the simulated network delays are fixed.  It would be excellent if some random variation could be made.