On the IO frontend, WipperSnapper devices flip "disconnected"/"connected" frequently. It's a pain because:

• it can wipe out frontend activity if you're in a form that relies on being connected
• it "junks up" a device's connection log with many spurious connection events

I believe this can be fixed entirely in the device code, per the following 3 snippets:

constant is set to 5 seconds:

#define WS_KEEPALIVE_INTERVAL_MS                                               \
  5000 ///< Session keepalive interval time, in milliseconds

broker is told "disconnect me if i don't see you after 5 seconds":

      WS._mqtt->setKeepAliveInterval(WS_KEEPALIVE_INTERVAL_MS / 1000);

device gives itself a half-second to:

• finish up whatever it was doing
• get the ping packet to the broker

void Wippersnapper::pingBroker() {
  // ping within keepalive-10% to keep connection open
  if (millis() > (_prv_ping + (WS_KEEPALIVE_INTERVAL_MS -
                               (WS_KEEPALIVE_INTERVAL_MS * 0.10)))) {

Analysis: the device is inadvertently giving itself a mere 500ms to finish up whatever it is doing and get a "ping" packet to the broker. So every 5 seconds, there's a chance this lands after the timeout, causing a "disconnect" following closely by a "connect".

We discussed quickly as a team to make sure this wasn't intended, and we agree it is not. It's more that it's not obvious this is how this all works!

Proposed Fix:
Instead of using 1 constant plus math to express everything, break it into 2 obvious constants and remove the math from the callsites.

// ...
#define WS_BROKER_KEEPALIVE_MS 10000 // maximum time without a ping before a disconnect
#define WS_DEVICE_PING_MS 5000 // minimum time before a ping
// ...
// tell the broker how long to wait for a ping
WS._mqtt->setKeepAliveInterval(WS_BROKER_KEEPALIVE_MS / 1000);
// ...
void Wippersnapper::pingBroker() {
  // if it's past time to send the next ping
  if (millis() > (_prv_ping + WS_DEVICE_PING_MS)
// ...

I hope this will fix the problem and be easier to reason about going forward.