* Once a log is retrieved, server adds an entry with this log id to a sorted set in Redis, scored by expiry time and broadcasts it to any other server instances.
* If a log is being tailed, server keeps the total number of lines in a Redis key and appends chunks of log data to a sorted set for that log scored by index of the first line.
* Chunks are split on fixed boundaries, in order to allow older entries to be purged by score without having to count the number of lines they contain first.
* Agent polls for requests to provide tail data via LogRpcService.UpdateLogTail, which calls LogTailService.WaitForTailNext. WaitForTailNext returns the index of the total line count for this log if it is being tailed (indicating the index of the next line that the agent should send to the server), or blocks until the log is being tailed.
* Once data is flushed to persistent storage, the number of flushed lines is added to LogRpcService._trimQueue and the line data is removed from Redis after LogRpcService.TrimAfter.
* Log node contains a "complete" flag indicating whether it is necessary to check for tail data.
#preflight none
[CL 23215856 by Ben Marsh in ue5-main branch]
BuildForMac.command was expecting an XCodeConfigIOS and TVOS, however those seemed to have never been checked in.
Additionally, TVOS doesn't support MetalRT before 16.0, so we need to add a whole bunch of ugly ifdefs to prevent compilation errors.
#jira none
#preflight 637731b1815e4b9b753267f0
[CL 23190759 by zack neyland in ue5-main branch]
