Function module_load_event 

#[unsafe(no_mangle)]
pub extern "C" fn module_load_event(
    _drctx: *mut c_void,
    module_ptr: *const module_data_t,
    _loaded: bool,
)

Called by DynamoRio when each C module is loaded. Each .dll will be a module, and the main binary itself will be comprised of one or more modules.