Retrofit module. Content-Type header is not passed

[zeldigas]

Configuration:

        <dependency>
            <groupId>com.squareup.retrofit2</groupId>
            <artifactId>retrofit</artifactId>
            <version>2.3.0</version>
        </dependency>
        <dependency>
            <groupId>org.asynchttpclient</groupId>
            <artifactId>async-http-client</artifactId>
            <version>2.4.3</version>
        </dependency>
        <dependency>
            <groupId>org.asynchttpclient</groupId>
            <artifactId>async-http-client-extras-retrofit2</artifactId>
            <version>2.4.3</version>
        </dependency>

I found that content type header is not passed properly to AHC's request. The problem is that content-type is contained in Body object (retrofit object), not in headers list, but this field is ignored in createRequest method of org.asynchttpclient.extras.retrofit.AsyncHttpClientCall

[slandelle]

@zeldigas Would you mind providing a PR? Extra modules are maintained by the community and I'm not a Retrofit user myself.

[zeldigas]

Sure, I'll do it this week.

[slandelle]

Cool, thanks!

[zeldigas]

PR created, please check and let me know if I need improve it somehow