Function message_to_wire 

pub fn message_to_wire(
    from: &str,
    value: &RuntimeValue,
) -> Result<Vec<u8>, String>

Encode a directed peer message for the relay wire: the sender’s inbox topic plus the FULL language value — scalars, collections, structs, inductives, nested, type tags and all — as compact bincode under the process default integrity ([default_integrity]). Closures, and channel/task handles (local to this process), cannot travel between machines and are reported with a clear error rather than silently dropped.