Hub -- java -jar /Users/$USER/Desktop/selenium-server-standalone-3.7.1.jar -role hub -hubConfig /Users/$USER/dexcom/hub.json
IOS -- appium --nodeconfig /Users/$USER/dexcom/nodeConfig_00008020-000614581A88003A.json -p 4724 --webdriveragent-port 8100 --default-capabilities '{"udid": "00008020-000614581A88003A"}'
Android -- appium --nodeconfig /Users/$USER/dexcom/nodeConfig_988c12384856463131.json -p 5724 --default-capabilities '{"udid": "988c12384856463131"}'