80d4423f997e15780bfa3f91bf4b4bf656b8ea45 Test buffered valid message (Troy Giorshev)
Pull request description:
This PR is a tweak of #19302. This sends a valid message.
Additionally, this test includes logging in the same vein as #19272.
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Depends on D9513
Backport of [[https://github.com/bitcoin/bitcoin/pull/19304 | core#19304]]