[#229] Refactoring Trace, AsyncTrace, DisableTrace and AsyncDisableTrace With TraceRoot

Author: feelform

lib/instrumentation/http-shared.js

@@ -18,7 +18,6 @@ const ServiceType = require('../context/service-type')
 const localStorage = require('./context/local-storage')
 const TraceBuilder = require('./context/trace-builder')
 const HttpRequestTraceBuilder = require('./http/http-request-trace-builder')
-const exp = require('constants')
 
 let pathMatcher
 const getPathMatcher = () => {