[bewo001]

I don't understand the difference to TCP here. If the path is not congested but the receiving endpoint is, the receiver can control the bandwidth by reducing the window size. Ultimately, it is always the sender that has to react to congestion by reducing the amount of traffic sent.

RPC is something of a red flag as well. RPCs will never behave like local procedure calls, so the abstraction will always leak (the pendulum of popularity keeps swinging back and forth between RPC and special purpose protocols every few years, though).