The animation of the entities a program sends itself, carried to each watching player as GoldSrc's engine carries entity_state_t's sequence, frame, animtime and framerate for every entity it sends (delta.lst).

server = QuakeServer.Animation.sample(server)
{states, server} = QuakeServer.Animation.take(server, 1)
states #=> %{374 => %{sequence: 0.0, time: 3.0, framerate: 1.0, animtime: 3.97}}

sample/1 runs once a server frame, at the server's time. For each live entity with a SendEntity, its state is sequence, the program's frame (the studio sequence); time, the program's frame1time (seconds into the sequence); animtime, the server's time; and framerate, how many seconds frame1time moved for each second the server's time moved since the entity's last sample in the same sequence. When the sequence changes or frame1time goes back, the framerate stays the last one measured; an entity sampled the first time has framerate 0. A program without a frame1time field has no animation.

take/2 gives the states of the entities the player holds (QuakeServer.Network.held/2) that the player was not sent yet, or whose state is not the one the player can work out from the state last sent: its sequence or framerate differs, or its time differs by more than a thousandth of a second from the last time moved on at the last framerate to the new animtime. GoldSrc's client shows the sequence at time + (now - animtime) * framerate seconds, and with no time passed since animtime at time.