Function wasi_config_set_stderr_custom 

#[unsafe(no_mangle)]
pub extern "C" fn wasi_config_set_stderr_custom(
    config: &mut wasi_config_t,
    callback: extern "C" fn(*mut c_void, *const u8, usize) -> isize,
    data: *mut c_void,
    finalizer: Option<extern "C" fn(*mut c_void)>,
)