# Identifying string. Must be unique in the topic namespace
# that this server works on.
string server_id

# Sequence number.
# The client will use this to detect if it has missed a subsequent
# update.  Every update message will have the same sequence number as
# an init message.  Clients will likely want to unsubscribe from the
# init topic after a successful initialization to avoid receiving
# duplicate data.
uint64 seq_num

# All markers.
InteractiveMarker[] markers