toString method Null safety

@override String toString()

Provides a string description of the AuthorizationException.

Implementation

@override
String toString() {
  var header = 'OAuth authorization error ($error)';
  if (description != null) {
    header = '$header: $description';
  } else if (uri != null) {
    header = '$header: $uri';
  }
  return '$header.';
}