Currently, during collection cloning phase, we execute lot of remote command request to sync target with RemoteCommandRequest::kNoTimeout. And, this can lead to issues where sync target can hang forever on those remote commands if there is some kind of network issue reaching the sync source. My suggestion would be setting some deadline to those remote commands like we do it for oplog fetching. When the command times out,  initial sync fails. This at least will allow the sync target to retry the initial sync with different sync source.

Below is the list of those remote commands issued with kNoTimeout.
1) List databases
2) List collections
3) Count collection
4) List indexes