Function safe_app::ffi::mutable_data::mdata_list_keys

#[no_mangle]
pub unsafe extern "C" fn mdata_list_keys(
    app: *const App, 
    info: *const MDataInfo, 
    user_data: *mut c_void, 
    o_cb: extern "C" fn(user_data: *mut c_void, result: *const FfiResult, keys: *const MDataKey, keys_len: usize)
)

Get list of all keys in the mutable data.

Callback parameters: user data, error code, vector of keys, vector size