code: public static SslContextBuilder forServer(File keyCertChainFile, File keyFile) {
          return new SslContextBuilder(true).keyManager(keyCertChainFile, keyFile);
      }
docs: Creates a builder for new server-side {@link SslContext}.
  
  @param keyCertChainFile an X.509 certificate chain file in PEM format
  @param keyFile a PKCS#8 private key file in PEM format
  @see #keyManager(File, File)