code: public B tls(File keyCertChainFile, File keyFile, @Nullable String keyPassword,
                   Consumer<SslContextBuilder> tlsCustomizer) throws SSLException {
          requireNonNull(keyCertChainFile, "keyCertChainFile");
          requireNonNull(keyFile, "keyFile");
          requireNonNull(tlsCustomizer, "tlsCustomizer");
  
          if (!keyCertChainFile.exists()) {
              throw new SSLException("non-existent certificate chain file: " + keyCertChainFile);
          }
          if (!keyCertChainFile.canRead()) {
              throw new SSLException("cannot read certificate chain file: " + keyCertChainFile);
          }
          if (!keyFile.exists()) {
              throw new SSLException("non-existent key file: " + keyFile);
          }
          if (!keyFile.canRead()) {
              throw new SSLException("cannot read key file: " + keyFile);
          }
  
          tls(buildSslContext(() -> SslContextBuilder.forServer(keyCertChainFile, keyFile, keyPassword),
                              tlsCustomizer));
          return self();
      }
docs: Configures SSL or TLS of this {@link VirtualHost} with the specified {@code keyCertChainFile},
  {@code keyFile}, {@code keyPassword} and {@code tlsCustomizer}.