public static JSONObject of(String key, Object value) {
        JSONObject object = new JSONObject(1, 1F);
        object.put(key, value);
        return object;
    }
Pack a pair of key-values as {@link JSONObject}

<pre>
JSONObject jsonObject = JSONObject.of("name", "fastjson2");
</pre>

@param key the key of the element
@param value the value of the element
core/src/main/java/com/alibaba/fastjson2/JSONObject.java