RpcDispatcher: non-reflective method invocations

Running a native image produced by the GraalVM AOT (ahead-of-time) compiler prohibits the use of Java Reflection.
However, RpcDispatcher uses java.lang.reflect.Method to invoke remote method calls.

Goal

Provide a mode (in MethodCall) which doesn't require a MethodLookup table but rather takes user-provided code (e.g. a lambda) to find and invoke the correct method.
This could be done by introducing an additional mode in MethodCall based on ID which calls the (user-provided) lambda to invoke a method. The lambda would read the arguments and invoke the method based on the received ID, then return the result.