Implement kotlin sample

[Amir-yazdanmanesh]

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Issue Reference: Retrofit Kotlin examples #4205

This PR introduces a Kotlin sample that demonstrates how to use Retrofit in conjunction with RxJava to fetch GitHub repositories for a specified user.

• Added a Kotlin example that fetches repositories from the GitHub API using Retrofit and RxJava.

[kungpaogao]

+1, this would be nice to have, but could we also use coroutines as well to make it even more Kotlin? (edit: just found this PR #3500)

Also, it would be good to have Kotlin examples on the homepage.

[Amir-yazdanmanesh]

+1, this would be nice to have, but could we also use coroutines as well to make it even more Kotlin? (edit: just found this PR #3500)

Also, it would be good to have Kotlin examples on the homepage.

While using coroutines would indeed make the implementation more idiomatic to Kotlin, I decided to go with the current libraries in the module to avoid introducing new dependencies. Adding a new library to a project like Retrofit requires the owner's permission, and in this case, I wanted to demonstrate how we can work within the existing setup, using RxJava, which is already integrated. This keeps the implementation aligned with the current project dependencies while still showcasing Kotlin features.