1. A computer system for a remote procedure call (RPC) with call-by-reference semantics, comprising: a memory having computer readable computer instructions; and a processor for executing the computer readable instructions to perform a method comprising: establishing a session between a client and a server; initializing a session heap memory with a remote direct memory access (RDMA) provider of the client; storing a parameter in the session heap memory; passing a handle for the parameter to the server; and permitting access to the parameter responsive to an on-demand request from the server.