This is my test output when I say warningLogger: logger.warn
:
{"level":"info","time":1587619076038,"pid":14312,"hostname":"precision5510","msg":"Uncaught error {}","v":1}
{"level":"error","time":1587619076040,"pid":14312,"hostname":"precision5510","isAPIError":true,"statusCode":500,"msg":"this[writeSym] is not a function","stack":"Error: this[writeSym] is not a function\n at SwapHandlers.<anonymous> (/home/gene/dev/0x-api/src/handlers/swap_handlers.ts:185:19)\n at Generator.throw (<anonymous>)\n at rejected (/home/gene/dev/0x-api/lib/src/handlers/swap_handlers.js:5:65)\n at <anonymous>\n at process._tickCallback (internal/process/next_tick.js:189:7)","type":"Error","v":1}
{"level":"info","time":1587619076047,"pid":14312,"hostname":"precision5510","req":{"url":"/swap/v0/price","method":"GET","headers":{"user-agent":"node-superagent/3.8.3","host":"127.0.0.1:45239"},"body":{},"query":{"buyToken":"ZRX","sellToken":"WETH","sellAmount":"100000000000000000","takerAddress":"0x6ecbe1db9ef729cbe97