src/main/java/io/reactivex/plugins/RxJavaPlugins.java
@SuppressWarnings({ "rawtypes", "unchecked" })
    @NonNull
    public static <T> Observable<T> onAssembly(@NonNull Observable<T> source) {
        Function<? super Observable, ? extends Observable> f = onObservableAssembly;
        if (f != null) {
            return apply(f, source);
        }
        return source;
    }
@SuppressWarnings({ "rawtypes", "unchecked" })
    @NonNull
    public static <T> Observable<T> onAssembly(@NonNull Observable<T> source) {
        Function<? super Observable, ? extends Observable> f = onObservableAssembly;
        if (f != null) {
            return apply(f, source);
        }
        return source;
    }
@ SuppressWarnings ( { "rawtypes" , "unchecked" } ) @ NonNull public static < T > Observable < T > onAssembly ( @ NonNull Observable < T > source ) { Function < ? super Observable , ? extends Observable > f = onObservableAssembly ; if ( f != null ) { return apply ( f , source ) ; } return source ; }
Calls the associated hook function.
@param <T> the value type
@param source the hook's input value
@return the value returned by the hook
Calls the associated hook function .