Firebase Performance Plugin causing slow build time

When using Firebase Performance in Android Studio the gradle task app:transformClassesWithFirebasePerformancePluginForDebug is taking significantly longer than any other task and is therefore dramatically slowing down my gradle build times.

Slow Build shown in Profiler

Firebase in our project caused 40% build time increase. To speed up debug builds we added a possibility to switch it on/off using build parameters in app/build.gradle and root build.gradle files:

app:

if (!project.hasProperty("disable-performance-plugin"))  {
    apply plugin: 'com.google.firebase.firebase-perf' 
}

root/buildscript/dependencies:

if (!project.hasProperty("disable-performance-plugin")) {
    classpath('com.google.firebase:firebase-plugins:1.1.5') {
        exclude group: 'com.google.guava', module: 'guava-jdk5'
    }
}

when running from the command line use

./gradlew your-task  -Pdisable-performance-plugin

when working from Android Studio, add the flag to compiler options: