ولی قبل از اون، مدیریت کد ناهم‌زمان خیلی پیچیده‌تر و سخت‌تر بود.

توی نسخه‌های قبلی پایتون، می‌تونستی از نخ‌ها یا <a href="https://www.gevent.org/" class="external-link" target="_blank">Gevent</a> استفاده کنی. ولی کد خیلی پیچیده‌تر می‌شه برای فهمیدن، دیباگ کردن و فکر کردن بهش.

توی نسخه‌های قبلی NodeJS / جاوااسکریپت مرورگر، از "کال‌بک‌ها" استفاده می‌کردی. که می‌رسید به "جهان کال‌بک‌ها".

   * @param array the array in which to place the collection elements
   * @throws ArrayStoreException if the runtime type of the specified array is not a supertype of
   *     the runtime type of every element in the specified collection
   */
  static <T extends @Nullable Object> T[] toArrayImpl(Collection<?> c, T[] array) {
    int size = c.size();
    if (array.length < size) {
      array = newArray(array, size);

			},
			expectedSync: true,
		},
		{ // 7. existing object replication enabled, versioning enabled, replication status unset & reset ID present
			name: "existing object replication with reset in progress and object never replicated before",
			info: ObjectInfo{
				Size:              100,
				ReplicationStatus: replication.StatusType(""),
				VersionID:         "a3348c34-c352-4498-82f0-1098e8b34df9",

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