For example, when installed from GitHub (as opposed to from a prepackaged archive),
  the Flutter tool will download the Dart SDK from Google servers immediately when
  first run, as it is used to execute the flutter tool itself. This will also
  occur when Flutter is upgraded (e.g. by running the flutter upgrade command).

The flutter tool uses Google Analytics to report feature usage
  statistics and send crash reports. This data is used to help improve Flutter
  tools over time.

Flutter tool analytics are not sent on the very first run. To disable
  reporting, run flutter config --no-analytics. To display the current
  setting, use flutter config. If you opt out of analytics, an opt-out
  event is sent, and then no further information is sent by the
  Flutter tool.

Dart tools may also send usage metrics and crash reports to Google.
  To control the submission of these metrics, use the following options on the
  dart tool: