Include the build_runner's timestamp in our source code.

1. Add build_timestasmp to pubspec.yaml.

   name: my_pkg
   version: 1.2.3
   dev_dependencies:
     build_runner: ^1.0.0
     build_timestamp: ^0.1.0
   

2. Run a build.

   > dart pub run build_runner build
   

   lib/src/timestamp.dart will be generated with content:

   // Generated code. Do not modify.
   const packageMillisecondsSinceEpoch = <MILLISECONDS_SINCE_EPOCH>;
   

To change the path of the generated file, create a build.yaml in the root of your package. By changing the output option of this builder, the path can be customized:

targets:
  $default:
    builders:
      build_timestamp:
        options:
          output: lib/src/custom/path/to/timestamp.dart