Placed the dependency at the first position in the list and stored the version number in an argument.

build.gradle

@@ -29,6 +29,7 @@ buildscript {
         streamsupportVersion = '1.7.2'
         threetenabpVersion = '1.2.4'
         zxingEmbeddedVersion = '3.6.0'
+        tunnelVersion = '1.0.20200407'
 
         groupName = 'com.wireguard.android'
     }

ui/build.gradle

@@ -65,6 +65,7 @@ android {
 }
 
 dependencies {
+    implementation "com.wireguard.android:tunnel:$tunnelVersion"
     implementation "androidx.annotation:annotation:$annotationsVersion"
     implementation "androidx.appcompat:appcompat:$appcompatVersion"
     implementation "androidx.constraintlayout:constraintlayout:$constraintLayoutVersion"
@@ -80,7 +81,6 @@ dependencies {
     implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:$coroutinesVersion"
     implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:$coroutinesVersion"
     implementation "net.sourceforge.streamsupport:android-retrofuture:$streamsupportVersion"
-    implementation 'com.wireguard.android:tunnel:1.0.20200407'
 }
 
 tasks.withType(JavaCompile) {