doc: add tip for session.post function

Author: theanarkh

doc/api/inspector.md

@@ -325,6 +325,10 @@ by V8. Chrome DevTools Protocol domain provides an interface for interacting
 with one of the runtime agents used to inspect the application state and listen
 to the run-time events.
 
+Note that, you can not set `reportProgress` to `true` when post
+`HeapProfiler.takeHeapSnapshot` or `HeapProfiler.stopTrackingHeapObjects`
+command to V8.
+
 #### Example usage
 
 Apart from the debugger, various V8 Profilers are available through the DevTools