Hide 408 Telemetry Requests in Fiddler
Symptoms
Fiddler capture can show Windows/Watson Telemetry requests. These appear as HTTP status 408 (request timeout). Microsoft telemetry calls to v10.vortex-win.data.microsoft.com bypass the filters and add noise.

Cause
Fiddler's filters are not effective where there are protocol violations. The response body reports a message similar to "The request body did not contain the specified number of bytes. Got 0, expected 4,814"
Resolution
One of two methods:
Easy
'Do nothing' if protocol violations are observed. This may inadvertently hide sessions you are interested in.

Involved
For best results, put this code inside OnPeekAtRequestHeaders:
\${NL}if (oSession.uriContains("watson.telemetry.microsoft.com")) { oSession["ui-hide"] = "stealth-boring boring boring...."; } \${NL}