What is "postprocessing" block inside the 'release' block in app level gradle file in Android Studio?

Below is the snipet of app level gradle file.

 buildTypes {
    release {

        postprocessing {
            removeUnusedCode false
            removeUnusedResources false
            obfuscate false
            optimizeCode false
            proguardFile 'proguard-rules.pro'
        }
    }
}

Here, 'postprocessing' seems new in the gradle file. What does it mean? Android studio shows error while adding 'setMinifyEnabled true' along with it.

Studio Error: Error:The setMinifyEnabled true method cannot be used with together with the postprocessing