Buffering messages by receiving a message from a messaging client, writing the message to a logically-contiguous write-available region of a message buffer starting at a logically next write-available location within the write-available region, updating a head index to indicate a head boundary between a logically last message in the message buffer and a logically next write-available location in the message buffer, defining a packet including the message within the message buffer, transmitting a packet that includes a logically first message in the message buffer, and updating a tail index to indicate a tail boundary between a new logically last write-available location in the message buffer and a new logically first message in the message buffer.