static BlobIDAndVersion fromJson(String json) throws JSONException {
      JSONObject object = new JSONObject(json);
      String blobID = object.getString(BLOBID_KEY);
      int version = object.getInt(VERSION_KEY);
      return new BlobIDAndVersion(blobID, version);
    }
Deserialize a string that carries a json object to an {@link BlobIDAndVersion}.
@param json The string that carries a json object.
@return A {@link BlobIDAndVersion} object.
@throws JSONException If parsing the string to {@link JSONObject} fails.
ambry-account/src/main/java/com/github/ambry/account/RouterStore.java