Create debug-network-requests-chrome.md (#573)

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Author: yi-gu

explorations/debug-network-requests-chrome.md

@@ -0,0 +1,31 @@
+While the Chrome team is trying to integrate FedCM into devtools, we suggest developers to use the following tools to debug network requests.
+
+1. Open chrome://net-export from the URL bar. Select “Include raw bytes” and
+click “Start Logging to Disk”. Select a location to save the logs when prompted.
+<p align="center">
+     <img width="467" src="https://github.com/fedidcg/FedCM/blob/main/explorations/static/net-export/net-export-entry.png?raw=true"/>
+</p>
+2. Open the page that calls the FedCM API. e.g. https://webid-fcm.glitch.me
+<p align="center">
+     <img width="467" src="https://github.com/fedidcg/FedCM/blob/main/explorations/static/net-export/fedcm-1.png?raw=true"/>
+</p>
+3. Go through the FedCM flow to debug all network requests
+<p align="center">
+     <img width="467" src="https://github.com/fedidcg/FedCM/blob/main/explorations/static/net-export/fedcm-2.png?raw=true"/>
+</p>
+4. Stop the logging on chrome://net-export
+<p align="center">
+     <img width="467" src="https://github.com/fedidcg/FedCM/blob/main/explorations/static/net-export/net-export-stop.png?raw=true"/>
+</p>
+5. Load the logs into https://netlog-viewer.appspot.com/
+<p align="center">
+     <img width="467" src="https://github.com/fedidcg/FedCM/blob/main/explorations/static/net-export/netlog-viewer-entry.png?raw=true"/>
+</p>
+6. Under `Events` from the left, filter the logs with `type:URL_REQUEST`
+<p align="center">
+     <img width="467" src="https://github.com/fedidcg/FedCM/blob/main/explorations/static/net-export/netlog-viewer-example.png?raw=true"/>
+</p>
+7. The network requests that were sent to different endpoints can be viewed
+individually. They also include the response that the browser has received. If
+raw bytes are selected from step 1, the detailed response such as name, token
+string etc. will show up on the right.