使用通用類和函式

Created: November-22, 2018

建立泛型類例項：

var stringRunnable = new Runnable<string>();

執行通用功能：

function runSafe<T extends Runnable<U>, U>(runnable: T);

// Specify the generic types:
runSafe<Runnable<string>, string>(stringRunnable);

// Let typescript figure the generic types by himself:
runSafe(stringRunnable);