Постоянная SECONDS_PER_HOUR
int SECONDS_PER_HOUR = SECONDS_PER_MINUTE * MINUTES_PER_HOUR
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/1.24.3/dart-core/Duration/SECONDS_PER_HOUR-constant.html
