Function module_init 

pub unsafe extern "C" fn module_init(msg: *mut *const c_char) -> c_int

Called after server sends the INIT command

msg is an optional out-pointer to a malloc’d C string with your response.

Returning a non-zero code from the function will abort module startup.

Your module implementation must export it’s own version of this function as:

#[unsafe(no_mangle)]
unsafe extern "C" fn module_init(msg: *mut *const raw::c_char) -> raw::c_int {
    0  // Stub implementation
}