Base64Encoder.urlSafe const constructor
const Base64Encoder.urlSafe(Source
const Base64Encoder.urlSafe() : _urlSafe = true;© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/1.24.3/dart-convert/Base64Encoder/Base64Encoder.urlSafe.html