Function melib::gpgme::bindings::gpgme_set_progress_cb

pub unsafe extern "C" fn gpgme_set_progress_cb(
    c: *mut gpgme_context, 
    cb: Option<unsafe extern "C" fn(opaque: *mut c_void, what: *const c_char, type_: c_int, current: c_int, total: c_int)>, 
    hook_value: *mut c_void
)