src/main/java/io/reactivex/plugins/RxJavaPlugins.java
@NonNull
    static <T, R> R apply(@NonNull Function<T, R> f, @NonNull T t) {
        try {
            return f.apply(t);
        } catch (Throwable ex) {
            throw ExceptionHelper.wrapOrThrow(ex);
        }
    }
@NonNull
    static <T, R> R apply(@NonNull Function<T, R> f, @NonNull T t) {
        try {
            return f.apply(t);
        } catch (Throwable ex) {
            throw ExceptionHelper.wrapOrThrow(ex);
        }
    }
Wraps the call to the function in try-catch and propagates thrown
checked exceptions as RuntimeException.
@param <T> the input type
@param <R> the output type
@param f the function to call, not null (not verified)
@param t the parameter value to the function
@return the result of the function call