# 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 an update.
uint64 seq_num

# Type holds the purpose of this message.  It must be one of UPDATE or KEEP_ALIVE.
# UPDATE: Incremental update to previous state.
#         The sequence number must be 1 higher than for
#         the previous update.
# KEEP_ALIVE: Indicates the that the server is still living.
#             The sequence number does not increase.
#             No payload data should be filled out (markers, poses, or erases).
uint8 KEEP_ALIVE = 0
uint8 UPDATE = 1

uint8 type

# Note: No guarantees on the order of processing.
#       Contents must be kept consistent by sender.

# Markers to be added or updated
InteractiveMarker[] markers

# Poses of markers that should be moved
InteractiveMarkerPose[] poses

# Names of markers to be erased
string[] erases