title: Retrofit 2.4.0 with proguard
body: <p>When  I add Retrofit 2.4.0 library to android project  &gt;</p>
  <pre><code>implementation 'com.squareup.retrofit2:retrofit:2.4.0'
  </code></pre>
  <p>and set minifyEnabled {true}</p>
  <pre><code> buildTypes {
          release {
              minifyEnabled true
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
          }
      }
  </code></pre>
  <p>and then add these rules to proguard-rules.pro</p>
  <pre><code>-keep class com.squareup.** { *; }
  -keep interface com.squareup.** { *; }
  -keep class retrofit2.** { *; }
  -keep interface retrofit2.** { *;}
  -keep interface com.squareup.** { *; }
  
  
  -keepclasseswithmembers class * {
      @retrofit2.http.* &lt;methods&gt;;
  }
  
  
  -dontwarn rx.**
  -dontwarn retrofit2.**
  -dontwarn okhttp3.**
  -dontwarn okio.**
  </code></pre>
  <p>Finally built and generated signed apk successfully but the issue is when run the  ( release apk) &gt;  Retrofit requests not send and return { null } ..
  Whats the solution Please!</p>