Http client in `datamuse_api_client.dart` is never closed.

[Luckey-Elijah]

The http client created is never closed in datamuse_api_client.dart#L33. As per the http package docs:

It's important to close each client when it's done being used; failing to do so can cause the Dart process to hang.

Perhaps it's not a "serious" issue with a single un-closed client, such as this example project. But would something like this become an issue as a project scales?