code: func (gServer *GRPCServer) MutualTLSRequired() bool {
  	return gServer.tlsConfig != nil &&
  		gServer.tlsConfig.ClientAuth ==
  			tls.RequireAndVerifyClientCert
  }
docs: // MutualTLSRequired is a flag indicating whether or not client certificates
  // are required for this GRPCServer instance