POST /tips HTTP/1.1
    Host: alto.example.com
    Accept: application/alto-tips+json, application/alto-error+json
    Authorization: Basic Y2xpZW50MTpoZWxsb2FsdG8K
    Content-Type: application/alto-tipsparams+json
    Content-Length: 41

    {
      "resource-id": "my-routingcost-map"
    }

    HTTP/1.1 401 UNAUTHORIZED
    WWW-Authenticate: Digest
        realm="alto.example.com",
        qop="auth",
        algorithm="MD5",
        nonce="173b5aba4242409ee2ac3a4fd797f9d7",
        opaque="a237ff9ab865379a69d9993162ef55e4"

    POST /tips HTTP/1.1
    Host: alto.example.com
    Accept: application/alto-tips+json, application/alto-error+json
    Authorization: Digest
        username="client1",
        realm="alto.example.com",
        uri="/tips",
        qop=auth,
        algorithm=MD5,
        nonce="173b5aba4242409ee2ac3a4fd797f9d7",
        nc=00000001,
        cnonce="ZTg3MTI3NDFmMDQ0NzI1MDQ3MWE3ZTFjZmM5MTNiM2I=",
        response="8e937ae696c1512e4f990fa21c7f9347",
        opaque="a237ff9ab865379a69d9993162ef55e4"
    Content-Type: application/alto-tipsparams+json
    Content-Length: 41

    {
      "resource-id": "my-routingcost-map"
    }


    HTTP/1.1 200 OK
    Content-Type: application/alto-tips+json
    Content-Length: 258

    {....}