Cap’n Proto RPC:

Cap’n Proto RPC employs TIME TRAVEL! The results of an RPC call are returned to the client instantly, before the server even receives the initial request!

There is, of course, a catch: The results can only be used as part of a new request sent to the same server. If you want to use the results for anything else, you must wait.

However, Cap’n Proto promises support an additional feature: pipelining. The promise actually has methods corresponding to whatever methods the final result would have, except that these methods may only be used for the purpose of calling back to the server. Moreover, a pipelined promise can be used in the parameters to another call without waiting.

An interesting feature which limits the number of network hops in the query is a pipeline of dependent requests.