As a temporary solution, we added worker_name_to_id to the rpc init API to simplify RpcAgent initialization process. Ideally, each RpcAgent implementation should either communicate directly to collect all names or read the names from the store (initialized by using the init_method arg). If it is too complicated to add the name support in store for now, we could use a temporary process group instance during the initialization to all gather names. Bottom line is that worker_name_to_id should not appear in the final API.

cc @pietern @mrshenli @pritamdamania87 @zhaojuanmao @satgera @gqchen @aazzolini @rohan-varma @xush6528