This library isn't null safe

Is your feature request related to a problem? Please describe. This library isn't null-safe. As a result, warnings are thrown in IDEs.

Here's an example of importing the library into a Flutter project in VSCode.

Describe the solution you'd like This library should be migrated. https://dart.dev/null-safety/migration-guide#step2-migrate

In addition to warnings in the ide, it requires --no-sound-null-safety to compile, which generates a warning that the option will not be supported in flutter 3