code: func (c *Page) CaptureSnapshot(format string) (string, error) {
  	var v PageCaptureSnapshotParams
  	v.Format = format
  	return c.CaptureSnapshotWithParams(&v)
  }
docs: // CaptureSnapshot - Returns a snapshot of the page as a string. For MHTML format, the serialization includes iframes, shadow DOM, external resources, and element-inline styles.
  // format - Format (defaults to mhtml).
  // Returns -  data - Serialized page data.