While there may be data remaining in the buffer, there might not be enough to decode another transport packet. Thus it is not correct to only consider the remaining number of bytes in the buffer as a condition of continuing to process data. Fortunately there is a demain hint that is set when someone asks for more data than a stream reader can provide. This can be used to differentiate between data remaining in the buffer, and not being able to do anything more with it.
#rb martin.ridgers, johan.berg
#rm 5.0
#ushell-cherrypick of 18267675 by Martin.Ridgers
#jira UE-134430, UE-135475
#preflight 619cf19cf70a9e92db3b69f7
[CL 18269671 by Johan Berg in ue5-main branch]
#rnx
#rb none
#ROBOMERGE-SOURCE: CL 10869240 via CL 10869516 via CL 10869902
#ROBOMERGE-BOT: (v613-10869866)
[CL 10870584 by ryan durand in Main branch]
