copyWhenLoadingMore method
create new instance of FetchingState.
set status to LoadState.loadingMore
keep the current data and error or user can pass in those parameter.
this is helpful when you want to add more data into current data
Implementation
FetchingState<T> copyWhenLoadingMore() {
return FetchingState(
fetchingStatus: LoadState.loadingMore,
data: data,
);
}