The GDL90 is "standard" with the exception of three non-standard GDL90-style messages: `0xCC` (stratux heartbeat), `0x5358` (another stratux heartbeat), and `0x4C` (AHRS report).
2. Look for Wi-Fi network that **starts with** "stratux".
3. Detect 192.168.10.0/24 Wi-Fi connection, verify stratux status with JSON response from ws://192.168.10.1/status.
See main/gen_gdl90.go:makeStratuxHeartbeat() for heartbeat format.
### Sleep mode
Stratux makes use of of ICMP Echo/Echo Reply and ICMP Destination Unreachable packets to determine the state of the application receiving GDL90 messages.
*Queueable messages* includes all UAT uplink messages, and in general: any messages whose value will not degrade for having been delayed for
the typical "sleep mode" period, whose content remains accurate despite said delay, and whose content is sufficiently redundant such
that if the typical delay period is exceeded then it can be discarded.
When a client enters sleep mode, queueable messages are entered into a FIFO queue of fixed size which should be sufficient to hold 10-25 minutes of
data per client.
There are three cases that are used to detect the state of a client:
1. Responding to ICMP Echo AND no ICMP Destination Unreachable received for destination port => not sleeping.
2. Not responding to ICMP Echo => sleeping.
3. Responding to ICMP Echo AND ICMP Destination Unreachable received for destination port => sleeping.
It is important to note that NEXRAD frames, METARs, and Winds Aloft may be delayed in reception. The timestamp in the GDL90 message should always
be used to for the observation time, and not the time the message was received.
*`http://192.168.10.1/setSettings` - set device settings. Use an HTTP POST of JSON content in the format given above - posting only the fields containing the settings to be modified.
*`http://192.168.10.1/getSituation` - get GPS/AHRS information. Example output:
*`ws://192.168.10.1/traffic` - traffic stream. On initial connect, all currently tracked traffic targets are dumped. Updates are streamed as they are received. Example output:
