doc:use `Buffer.byteLength` for Content-Length
As the description in http.md:
If the body contains higher coded characters then Buffer.byteLength() should be used to determine the number of bytes in a given encoding.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
As the description in http.md:
If the body contains higher coded characters then Buffer.byteLength() should be used to determine the number of bytes in a given encoding.