Ceph » rgw

When using CopyObject API to copy from a source bucket resist on a different zonegroup which needs to call fetch_remote_obj(). When the object is big enough that results in calls to `RGWCopyObj::progress_cb` and when `rgw_copy_obj_progress` is true, `send_partial_response` will try to write the progress to frontend socket which cause a race as the same yield context is used for curl to fetch the rest and as Casey stated "we have two different callers trying to suspend the same coroutine, we want our http thread to do nothing but service io for curl".