lib/node_tracers.js
function RawRESTkinHTTPTracer(traceUrl, keystoneClient) {
  if (traceUrl.charAt(traceUrl.length - 1) === '/') {
    traceUrl = traceUrl.slice(0, -1);
  }

  this._traceUrl = traceUrl;
  this._keystoneClient = keystoneClient;

  EndAnnotationTracer.call(this, this.sendTraces);
}
function RawRESTkinHTTPTracer(traceUrl, keystoneClient) {
  if (traceUrl.charAt(traceUrl.length - 1) === '/') {
    traceUrl = traceUrl.slice(0, -1);
  }

  this._traceUrl = traceUrl;
  this._keystoneClient = keystoneClient;

  EndAnnotationTracer.call(this, this.sendTraces);
}
A tracer that records to zipkin through the RESTkin http interface.
Requires a keystone client ({node-keystone-client}).

This implementation posts all traces immediately and does not implement
buffering.

@param {String} traceUrl The URL to the RESTkin endpoint including the
version. For example: https://example.com/v1.0
@param {keystone-client.KeystoneClient object} keystoneClient The
keystone client to use to authenticate against keystone to get a token
and tenant id.