if (platform == "jdk8alpn") {
    // Add alpn-boot on Java 8 so we can use HTTP/2 without a stable API.
    val alpnBootVersion = alpnBootVersion()
    if (alpnBootVersion != null) {
      val alpnBootJar = configurations.detachedConfiguration(
        dependencies.create("org.mortbay.jetty.alpn:alpn-boot:$alpnBootVersion")
      ).singleFile
      tasks.withType<Test> {
        jvmArgs("-Xbootclasspath/p:${alpnBootJar}")
      }

    else -> null
  }
}

/**
 * Returns the alpn-boot version specific to this OpenJDK 8 JVM, or null if this is not a Java 8 VM.
 * https://github.com/xjdr/xio/blob/master/alpn-boot.gradle
 */
fun alpnBootVersion(): String? {
  val version = System.getProperty("alpn.boot.version")

  if (version != null) {
    return version
  }

  val javaVersion = System.getProperty("java.version")