}
  }

  companion object {
    val logger: Logger = Logger.getLogger(Http2Server::class.java.name)

    @JvmStatic
    fun main(args: Array<String>) {
      if (args.size != 1 || args[0].startsWith("-")) {
        println("Usage: Http2Server <base directory>")
        return
      }
      val server =
        Http2Server(
          File(args[0]),
          localhost().sslContext().socketFactory,

The environment variable `GODEBUG`
can hold a comma-separated list of these settings.
For example, if a Go program is running in an environment that contains

	GODEBUG=http2client=0,http2server=0

then that Go program will disable the use of HTTP/2 by default in both
the HTTP client and the HTTP server.
It is also possible to set the default `GODEBUG` for a given program
(discussed below).