Add Undocumented Restriction to MessagingService Docs

[daftcube]

When I was doing testing, I found that there was a restriction for MessagingService messages to be less than ~= 1000 characters of encoded JSON text. Unless I’m blind, I don’t see this restriction stated anywhere on the MessagingService documentation page or the associated guide.

I think adding this documentation is particularly important because it clarifies that MessagingService is only meant for small amounts of communication, and this might not be 100% obvious to someone who is unfamiliar with cloud infrastructure.

[Ozzypig]

I’ll try and confirm the exact limit with an engineer internally, then update this thread. It’s unlikely, but it could be that the actual value isn’t defined, but has some practical limit.