"grpc_services": [
        {
          "google_grpc": {
            "target_uri": "{{ .discovery_address }}",
            "stat_prefix": "googlegrpcxds",
            "channel_credentials": {
              "ssl_credentials": {
                {{ with .xds_root_cert}}"root_certs": {"filename": "{{.}}"}{{ end }}
              }
            },
            "call_credentials": [{
            {{ if .sts }}
              "sts_service": {

// authentication.
func UnixCredentials(ucred *Ucred) []byte {
	b := make([]byte, CmsgSpace(SizeofUcred))
	h := (*Cmsghdr)(unsafe.Pointer(&b[0]))
	h.Level = SOL_SOCKET
	h.Type = SCM_CREDENTIALS
	h.SetLen(CmsgLen(SizeofUcred))
	*(*Ucred)(h.data(0)) = *ucred
	return b
}

// ParseUnixCredentials decodes a socket control message that contains

	RLIMIT_NOFILE                   = 6
	RLIMIT_MEMLIMIT                 = 7
	RLIMIT_MEMLOCK                  = 0x8
	RLIM_INFINITY                   = 2147483647
	SCHED_FIFO                      = 0x2
	SCM_CREDENTIALS                 = 0x2
	SCM_RIGHTS                      = 0x01
	SF_CLOSE                        = 0x00000002
	SF_REUSE                        = 0x00000001
	SHM_RND                         = 0x2

	SCHED_IDLE                                  = 0x5
	SCHED_NORMAL                                = 0x0
	SCHED_RESET_ON_FORK                         = 0x40000000
	SCHED_RR                                    = 0x2
	SCM_CREDENTIALS                             = 0x2
	SCM_PIDFD                                   = 0x4
	SCM_RIGHTS                                  = 0x1
	SCM_SECURITY                                = 0x3