Method send

src/Fetch.js:134–240

* Sends the request. * @param body The body of the request.

(body = null)

   * @param body The body of the request.
   */
  async send(body = null) {
    if (this.readyState !== 1) {
      throw new Error('send() can only be called when state is OPENED.');
    }

    this._abortController = new AbortController();
    const signal = this._abortController.signal;

    // Handle timeout
    let timeoutID;
    if (this.timeout > 0) {
      timeoutID = setTimeout(
        () => this._abortController.abort(new DOMException('The user aborted a request.', 'TimeoutError')),
        this.timeout
      );
    }

    const fetchOptions = {
      method: this._method,
      headers: this._headers,
      body: body,
      signal: signal,
      credentials: this.withCredentials ? 'include' : 'same-origin',
    };

    try {
      const response = await fetch(this._url, fetchOptions);

      // Populate response properties once headers are received
      this.status = response.status;
      this.statusText = response.statusText;
      this.responseURL = response.url;
      this._responseHeaders = response.headers;
      this._changeReadyState(2); // 2: HEADERS_RECEIVED

      // Start processing the body
      this._changeReadyState(3); // 3: LOADING

      if (!response.body) {
        throw new Error("Response has no body to read.");
      }

      const reader = response.body.getReader();
      const contentLength = +response.headers.get('Content-Length');

      let receivedLength = 0;
      // When streaming data don't collect all of the chunks into one large chunk. It's up to the
      // user to collect the data as it comes in.
      const chunks = this._streamData ? null : [];

      while (true) {
        const { done, value } = await reader.read();
        if (done) {
          break;
        }

        if (!this._streamData) {
          chunks.push(value);