Oddbean new post about login | logout if my event has a created_at in the future it will be available to be listed only when this datetime reaches?
On amethyst, yes.
it is scheduled by the client?
depends on the relay and what policy it enforces about this bitcoin allows something like 2 hours divergence for timestamps on blocks, technically it is ok if block times are not monotonic... but this is a flaw in a short block interval chain, that's how the Verge blockchain got timewarp attacked (stopping the clock and enabling an attacker to mint infinite coins with dozens of empty blocks with coinbases to addresses they control