The "price" for Fiddler is feedback, so you've paid more than most.
Please grab either of the latest Alphas:
Click Rules > Customize Rules.
Scroll to the OnPeekAtRequestHeaders
function (you may need to uncomment it).
Inside that function, add code similar to the following:
if (oSession.host.Contains("whatever.com") &&
oSession["ui-backcolor"] = "orange";
oSession["log-drop-request-body"] = "streamingThisRequest";
oSession.oRequest.BufferRequest = false;
This will cause the request in question to be streamed and forgotten as it is written.
Please do let me know how this works out. There are probably lots of interesting little corner cases that I missed.
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