code: public OkVolley init(Context context) {
          this.mContext = context;
          InstanceRequestQueue = newRequestQueue(context);
          mUserAgent = generateUserAgent(context);
          mRequestHeaders = new HashMap<>();
          mRequestHeaders.put(OkRequest.HEADER_USER_AGENT, mUserAgent);
          mRequestHeaders.put(OkRequest.HEADER_ACCEPT_CHARSET, OkRequest.CHARSET_UTF8);
          return this;
      }
docs: init method please call this method in Application
  
  @param context ApplicationContext
  @return this Volley Object