Add mitt and tailrec

[Edward-Roshan]

Please read How to contribute before creating a submission.

Description

mitt

• Dart event emitter/pubsub. inspired by npm mitt.

tailrec

• This package help you to convert recursive function into the while-loop codes. so that program won't meet out of memory that caused by stack overflow.

---

Checklist

• I read How to contribute
• I edited the SOURCE.md file only
• Added a link to the repo in the PR

---

Feel free to add this badge to your repository after it's accepted to awesome-flutter.

<a href="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/Solido/awesome-flutter">
   <img alt="Awesome Flutter" src="https://img.shields.io/badge/Awesome-Flutter-blue.svg?longCache=true&style=flat-square" />
</a>

[renancaraujo]

Hello there,

Read the the contributing again. Don’t commit in the rearme directly and keep one suggestion per pr.

[renancaraujo]

Unfit