Mac: Get Kerberos KRB5/GSS ticket (TGT) to use in REST API as negotiate header

Question

In addition to this question (Get KRB5/GSS status in Swift), how can I get the TGT ticket/token in swift via GSS API to use it in a HTTP REST client call to a Kerberos-secured REST API?

I can issue a TGT with the kinit command and find the gss_cred_id_t credential by using the GSS API, but I do not find any function to get the TGT token from it and use it for API communication (negotiate header is needed).

XCode + Swift:

gss_iter_creds(&min_stat, 0, nil, { oid, credential in
    if credential != nil {
        let lifetime = GSSCredentialGetLifetime(credential!)
         
        // HOW TO GET THE KERBEROS TOKEN (TGT) FROM THIS CREDENTIAL?
        var majorStatus: OM_uint32 = 0
        var minorStatus: OM_uint32 = 0
        var retFlags: OM_uint32 = 0
        var contextId: gss_ctx_id_t? // GSS_C_NO_CONTEXT
        var inBuffer: gss_buffer_desc = gss_buffer_desc()
        var token: gss_buffer_desc = gss_buffer_desc()
                    
        majorStatus = gss_init_sec_context(
            &minorStatus,
            credential,
            &contextId,
            name,
            nil,
            0,
            OM_uint32(GSS_C_INDEFINITE),
            nil,
            &inBuffer,
            nil,
            &token,
            &retFlags,
            nil)

        // HOW TO GET THE STRING VALUE OF VARIABLE 'token'
        // which is a 'gss_buffer_desc' data type to use as
        // negotiate header in REST call??

    }
})