* use https://lastminuteengineers.com/esp32-sleep-modes-power-consumption/ association sleep pattern to save power - but see https://github.com/espressif/esp-idf/issues/2070
* stop using loop() instead use a job queue and let cpu sleep
* move lora rx/tx to own thread and block on IO
* measure power consumption and calculate battery life assuming no deep sleep
* do lowest sleep level possible where BT still works during normal sleeping, make sure cpu stays in that mode unless lora rx packet happens, bt rx packet happens or button press happens
* optionally do lora messaging only during special scheduled intervals (unless nodes are told to go to low latency mode), then deep sleep except during those intervals - before implementing calculate what battery life would be with this feature
* see section 7.3 of https://cdn.sparkfun.com/assets/learn_tutorials/8/0/4/RFM95_96_97_98W.pdf and have hope radio wake only when a valid packet is received. Possibly even wake the ESP32 from deep sleep via GPIO.
* never enter deep sleep while connected to USB power (but still go to other low power modes)
* when main cpu is idle (in loop), turn cpu clock rate down and/or activate special sleep modes. We want almost everything shutdown until it gets an interrupt.
hardwire nodenums based on macaddr. when node boots it broadcasts its Owner info (which includes our macaddr). If any node receives Owner messages, the other nodes reply with their owner info.
Really should instead do something like: new node sends its owner info as a provisional request. If any other node shows that nodenum in use by a different macaddr, they reply with NodeDeny.
If the node doesn't get denied within X seconds it then sends the info as a non provisional message (and other nodes update their node db)
But fixme, think about this and look for standard solutions - it will have problems when meshes separate change and then rejoin.
* don't even power on bluetooth until we have some data to send to the android phone. Most of the time we should be sleeping in a lowpower "listening for lora" only mode. Once we have some packets for the phone, then power on bluetooth
until the phone pulls those packets. Ever so often power on bluetooth just so we can see if the phone wants to send some packets. Possibly might need ULP processor to help with this wake process.
* change the partition table to take advantage of the 4MB flash on the wroom: http://docs.platformio.org/en/latest/platforms/espressif32.html#partition-tables
* have MeshService keep a node DB by sniffing user messages
* have a state machine return the correct FromRadio packet to the phone, it isn't always going to be a MeshPacket. Do a notify on fromnum to force the radio to read our state machine generated packets
* sent/received packets (especially if a node was just reset) have variant of zero sometimes - I think there is a bug (race-condtion?) in the radio send/rx path.
