In VS2015 there was various stuff running in the background, like \"VsHub\", etc. It connected to MS servers, and possibly leaked stuff. So the common approach was to delete tho
I use Glasswire free edition* (https://www.glasswire.com/) to monitor outgoing network traffic. The free version is not 100% ideal as it only reports connections as they happen, where the paid for version has an "ask first" option, but costs $50 per pc! If you want to flog the money to buy the full version it has some firewall tools to pre-emptively block outgoing traffic, which might be good enough to give you peace of mind that VS isn't sending data off into the unknown.
Today it caught VS (d:\program files (x86)\microsoft visual studio\2017\community\common7\servicehub\hosts\servicehub.host.clr.x86\servicehub.host.clr.x86.exe
) initiating traffic to cs9.wpc.v0cdn.net
(v0cdn.net seems to be registered by Verizon when do a registrar lookup https://www.whois.com/whois/v0cdn.net) IP: 93.184.221.200
The best solution I could find was to add hosts file entries to block the communication and telemetry reporting. (granted, it's not a permanent fix)
Here's a list I compiled from various blogs - review it line-by-line for your own use as things like skype and windows updates might stop working due to the hosts file blocks.
# W10
0.0.0.0 cs1.wpc.v0cdn.net
0.0.0.0 df.telemetry.microsoft.com
0.0.0.0 i1.services.social.microsoft.com
0.0.0.0 i1.services.social.microsoft.com.nsatc.net
0.0.0.0 oca.telemetry.microsoft.com
0.0.0.0 oca.telemetry.microsoft.com.nsatc.net
0.0.0.0 pre.footprintpredict.com
0.0.0.0 reports.wes.df.telemetry.microsoft.com
0.0.0.0 sqm.telemetry.microsoft.com
0.0.0.0 sqm.telemetry.microsoft.com.nsatc.net
0.0.0.0 statsfe1.ws.microsoft.com
0.0.0.0 telecommand.telemetry.microsoft.com
0.0.0.0 telecommand.telemetry.microsoft.com.nsatc.net
0.0.0.0 telemetry.appex.bing.net
0.0.0.0 telemetry.urs.microsoft.com
0.0.0.0 vortex-sandbox.data.microsoft.com
0.0.0.0 vortex-win.data.microsoft.com
0.0.0.0 vortex.data.microsoft.com
# http://www.dslreports.com/forum/r30676597-Complete-Win10-blocking-host-file
#0.0.0.0 fe2.update.microsoft.com.akadns.net
#0.0.0.0 sls.update.microsoft.com.akadns.net
0.0.0.0 134.170.30.202
0.0.0.0 137.116.81.24
0.0.0.0 204.79.197.200
0.0.0.0 23.218.212.69
0.0.0.0 65.39.117.230
0.0.0.0 65.55.108.23
0.0.0.0 a-0001.a-msedge.net
0.0.0.0 a-0002.a-msedge.net
0.0.0.0 a-0003.a-msedge.net
0.0.0.0 a-0004.a-msedge.net
0.0.0.0 a-0005.a-msedge.net
0.0.0.0 a-0006.a-msedge.net
0.0.0.0 a-0007.a-msedge.net
0.0.0.0 a-0008.a-msedge.net
0.0.0.0 a-0009.a-msedge.net
0.0.0.0 a-msedge.net
0.0.0.0 a.ads1.msn.com
0.0.0.0 a.ads2.msads.net
0.0.0.0 a.ads2.msn.com
0.0.0.0 a.rad.msn.com
0.0.0.0 ac3.msn.com
0.0.0.0 ad.doubleclick.net
0.0.0.0 adnexus.net
0.0.0.0 adnxs.com
0.0.0.0 ads.msn.com
0.0.0.0 ads1.msads.net
0.0.0.0 ads1.msn.com
0.0.0.0 aidps.atdmt.com
0.0.0.0 aka-cdn-ns.adtech.de
0.0.0.0 apps.skype.com
0.0.0.0 arc.msn.com
0.0.0.0 az361816.vo.msecnd.net
0.0.0.0 az512334.vo.msecnd.net
0.0.0.0 b.ads1.msn.com
0.0.0.0 b.ads2.msads.net
0.0.0.0 b.rad.msn.com
0.0.0.0 bingads.microsoft.com
0.0.0.0 bs.serving-sys.com
0.0.0.0 c.atdmt.com
0.0.0.0 c.msn.com
0.0.0.0 cdn.atdmt.com
0.0.0.0 cds26.ams9.msecn.net
0.0.0.0 choice.microsoft.com
0.0.0.0 choice.microsoft.com.nsatc.net
0.0.0.0 compatexchange.cloudapp.net
0.0.0.0 corp.sts.microsoft.com
0.0.0.0 corpext.msitadfs.glbdns2.microsoft.com
0.0.0.0 db3aqu.atdmt.com
0.0.0.0 df.telemetry.microsoft.com
0.0.0.0 diagnostics.support.microsoft.com
0.0.0.0 ec.atdmt.com
0.0.0.0 edge.quantserve.com
0.0.0.0 fe2.update.microsoft.com.akadns.net
0.0.0.0 feedback.microsoft-hohm.com
0.0.0.0 feedback.search.microsoft.com
0.0.0.0 feedback.windows.com
0.0.0.0 flex.msn.com
0.0.0.0 fpt.live-partner.com
0.0.0.0 g.msn.com
0.0.0.0 h1.msn.com
0.0.0.0 i1.services.social.microsoft.com
0.0.0.0 i1.services.social.microsoft.com.nsatc.net
0.0.0.0 lb1.www.ms.akadns.net
0.0.0.0 live.rads.msn.com
0.0.0.0 m.adnxs.com
0.0.0.0 m.hotmail.com
0.0.0.0 msedge.net
0.0.0.0 msftncsi.com
0.0.0.0 msnbot-65-55-108-23.search.msn.com
0.0.0.0 msntest.serving-sys.com
0.0.0.0 oca.telemetry.microsoft.com
0.0.0.0 oca.telemetry.microsoft.com.nsatc.net
0.0.0.0 onesettings-bn2.metron.live.com.nsatc.net
0.0.0.0 onesettings-cy2.metron.live.com.nsatc.net
0.0.0.0 onesettings-db5.metron.live.com.nsatc.net
0.0.0.0 onesettings-hk2.metron.live.com.nsatc.net
0.0.0.0 pre.footprintpredict.com
0.0.0.0 preview.msn.com
0.0.0.0 pricelist.skype.com
0.0.0.0 rad.live.com
0.0.0.0 rad.msn.com
0.0.0.0 redir.metaservices.microsoft.com
0.0.0.0 reports.wes.df.telemetry.microsoft.com
0.0.0.0 rpt.msn.com
0.0.0.0 s.gateway.messenger.live.com
0.0.0.0 s0.2mdn.net
0.0.0.0 sO.2mdn.net
0.0.0.0 schemas.microsoft.akadns.net
0.0.0.0 secure.adnxs.com
0.0.0.0 secure.flashtalking.com
0.0.0.0 services.wes.df.telemetry.microsoft.com
0.0.0.0 settings-sandbox.data.microsoft.com
0.0.0.0 settings-win.data.microsoft.com
0.0.0.0 settings.data.glbdns2.microsoft.com
0.0.0.0 sls.update.microsoft.com.akadns.net
0.0.0.0 sqm.df.telemetry.microsoft.com
0.0.0.0 sqm.telemetry.microsoft.com
0.0.0.0 sqm.telemetry.microsoft.com.nsatc.net
0.0.0.0 ssw.live.com
0.0.0.0 static.2mdn.net
0.0.0.0 statsfe1.ws.microsoft.com
0.0.0.0 statsfe2.update.microsoft.com.akadns.net
0.0.0.0 statsfe2.ws.microsoft.com
0.0.0.0 survey.watson.microsoft.com
0.0.0.0 telecommand.telemetry.microsoft.com
0.0.0.0 telecommand.telemetry.microsoft.com.nsatc.net
0.0.0.0 telecommand.telemetry.microsoft.com.nsatc.net
0.0.0.0 telemetry.appex.bing.net
0.0.0.0 telemetry.appex.bing.net:443
0.0.0.0 telemetry.microsoft.com
0.0.0.0 telemetry.urs.microsoft.com
0.0.0.0 ui.skype.com
0.0.0.0 v10.vortex-win.data.metron.live.com.nsatc.net
0.0.0.0 v10.vortex-win.data.microsoft.com
0.0.0.0 view.atdmt.com
0.0.0.0 vortex-bn2.metron.live.com.nsatc.net
0.0.0.0 vortex-cy2.metron.live.com.nsatc.net
0.0.0.0 vortex-db5.metron.live.com.nsatc.net
0.0.0.0 vortex-hk2.metron.live.com.nsatc.net
0.0.0.0 vortex-sandbox.data.microsoft.com
0.0.0.0 vortex-win.data.metron.live.com.nsatc.net
0.0.0.0 vortex-win.data.microsoft.com
0.0.0.0 vortex.data.glbdns2.microsoft.com
0.0.0.0 vortex.data.metron.live.com.nsatc.net
0.0.0.0 vortex.data.microsoft.com
0.0.0.0 watson.live.com
0.0.0.0 watson.microsoft.com
0.0.0.0 watson.ppe.telemetry.microsoft.com
0.0.0.0 watson.telemetry.microsoft.com
0.0.0.0 watson.telemetry.microsoft.com.nsatc.net
0.0.0.0 wes.df.telemetry.microsoft.com
0.0.0.0 wes.df.telemetry.microsoft.comne