Function gbp_node_bootstrap_joiner 

#[unsafe(no_mangle)]
pub extern "C" fn gbp_node_bootstrap_joiner(
    h: i32,
    epoch: u64,
    expected_first_tid: u32,
) -> bool

Drives the node to ACTIVE as a joiner. expected_first_tid lets the joiner pre-arm pending transition state so that the first EXECUTE_TRANSITION after Welcome is accepted; pass 0 if the joiner recovered out-of-band and is already current.