if (done) {
          readable.push(null);
          return;
        }

        if (value &&
          typeof value.then === 'function') {
          return changeToAsyncValues(value);
        }

        if (value === null) {
          reading = false;
          throw new ERR_STREAM_NULL_VALUES();
        }

        if (readable.push(value)) {
          continue;
        }

        reading = false;
      } catch (err) {
        readable.destroy(err);
      }
      break;
    }
  }

  async function changeToAsyncValues(value) {
    isAsyncValues = true;

    try {
      const res = await value;

      if (res === null) {
        reading = false;
        throw new ERR_STREAM_NULL_VALUES();
      }

      if (readable.push(res)) {
        nextSyncWithAsyncValues();
        return;
      }

      reading = false;
    } catch (err) {
      readable.destroy(err);
    }
  }

  async function nextSyncWithAsyncValues() {
    for (;;) {
      try {
        const { value, done } = iterator.next();

        if (done) {
          readable.push(null);
          return;
        }

        const res = (value &&
          typeof value.then === 'function') ?
          await value :
          value;

        if (res === null) {
          reading = false;
          throw new ERR_STREAM_NULL_VALUES();
        }

        if (readable.push(res)) {
          continue;
        }

        reading = false;
      } catch (err) {
        readable.destroy(err);
      }
      break;
    }
  }

  async function nextAsync() {
    for (;;) {
      try {
        const { value, done } = await iterator.next();

        if (done) {
          readable.push(null);
          return;
        }

        if (value === null) {
          reading = false;
          throw new ERR_STREAM_NULL_VALUES();
        }

        if (readable.push(value)) {
          continue;
        }

        reading = false;
      } catch (err) {
        readable.destroy(err);
      }
      break;
    }
  }
  return readable;
}

module.exports = from;