We've added a new hello command that drivers/clients can use. However, we still extensively use the "isMaster" command internally in the RSM and various network/transport layers. We probably cannot change most instances since we must use isMaster to communicate with servers that don't support other protocols.

If we can't change the command we're using, perhaps we can still change local variables to reflect the new hello terminology. Either way, we should audit files in the client/, executor/, transport/, and rpc/ directories to determine which instances are worth changing.