I can watch my battery drain itself and below is the reason why. The tcpdump below shows that even while my iPhone is in "Low Power Mode" it is constantly communicating with Apple servers. In addition to being set to Low Power Mode, the phone is also logged out of iCloud and iTunes and Push settings have been disabled for email. Theoretically, the phone should show very limited network communication but instead, the network traffic is constant and the phone is hot to the touch. I've performed a "Home + Power" hard reset a number of times while watching the tcpdump output. Every time the phone reboots, it starts communicating with Apple's servers like mad...
20:49:29.786927 IP (tos 0x0, ttl 64, id 25941, offset 0, flags [none], proto UDP (17), length 44) 192.168.100.20.16403 > 17.155.127.222.16384: UDP, length 16
20:49:29.788165 IP (tos 0x0, ttl 64, id 49647, offset 0, flags [none], proto UDP (17), length 44) 192.168.100.20.16403 > 17.155.127.222.16385: UDP, length 16
20:49:29.788281 IP (tos 0x0, ttl 64, id 21506, offset 0, flags [none], proto UDP (17), length 44) 192.168.100.20.16403 > 17.155.127.223.16386: UDP, length 16
20:49:29.842063 IP (tos 0x0, ttl 55, id 0, offset 65376, flags [+], proto UDP (17), length 44, bad cksum 8d8b (->8d9f)!) 17.155.127.222 > 192.168.100.20: udp
20:49:29.844403 IP (tos 0x0, ttl 55, id 0, offset 65376, flags [+], proto UDP (17), length 44, bad cksum 8d8b (->8d9f)!) 17.155.127.222 > 192.168.100.20: udp
20:49:29.846038 IP (tos 0x0, ttl 54, id 0, offset 65376, flags [+], proto UDP (17), length 44, bad cksum 8e8a (->8e9e)!) 17.155.127.223 > 192.168.100.20: udp
20:49:30.555692 IP (tos 0x0, ttl 255, id 4133, offset 0, flags [none], proto UDP (17), length 63) 192.168.100.20.54982 > 192.168.100.1.53: 39600+ A? guzzoni.apple.com. (35)
20:49:30.568555 IP (tos 0x0, ttl 255, id 54590, offset 0, flags [none], proto UDP (17), length 55) 192.168.100.20.51639 > 192.168.100.1.53: 29501+ A? apple.com. (27)
20:49:30.570306 IP (tos 0x0, ttl 64, id 49601, offset 0, flags [none], proto UDP (17), length 408) 192.168.100.1.53 > 192.168.100.20.51639: 29501 3/8/8 apple.com. A 17.172.224.47, apple.com.[|domain]
20:49:30.591307 IP (tos 0x0, ttl 64, id 49602, offset 0, flags [none], proto UDP (17), length 456) 192.168.100.1.53 > 192.168.100.20.54982: 39600 3/10/5 guzzoni.apple.com. CNAME[|domain]
20:49:30.848066 IP (tos 0x0, ttl 64, id 54468, offset 0, flags [none], proto UDP (17), length 44) 192.168.100.20.16403 > 17.155.127.222.16384: UDP, length 16
20:49:30.848182 IP (tos 0x0, ttl 64, id 843, offset 0, flags [none], proto UDP (17), length 44) 192.168.100.20.16403 > 17.155.127.222.16385: UDP, length 16
20:49:30.848247 IP (tos 0x0, ttl 64, id 25580, offset 0, flags [none], proto UDP (17), length 44) 192.168.100.20.16403 > 17.155.127.223.16386: UDP, length 16
20:49:30.903435 IP (tos 0x0, ttl 55, id 0, offset 65376, flags [+], proto UDP (17), length 44, bad cksum 8d8b (->8d9f)!) 17.155.127.222 > 192.168.100.20: udp
20:49:30.906281 IP (tos 0x0, ttl 54, id 0, offset 65376, flags [+], proto UDP (17), length 44, bad cksum 8e8a (->8e9e)!) 17.155.127.223 > 192.168.100.20: udp
20:49:30.906409 IP (tos 0x0, ttl 55, id 0, offset 65376, flags [+], proto UDP (17), length 44, bad cksum 8d8b (->8d9f)!) 17.155.127.222 > 192.168.100.20: udp
20:49:31.467613 IP (tos 0x0, ttl 255, id 11990, offset 0, flags [none], proto UDP (17), length 142) 192.168.100.20.5353 > 224.0.0.251.5353: 0 [1au][|domain]
20:49:31.946829 IP (tos 0x0, ttl 64, id 25045, offset 0, flags [none], proto UDP (17), length 44) 192.168.100.20.16403 > 17.155.127.222.16384: UDP, length 16
20:49:31.947256 IP (tos 0x0, ttl 64, id 47153, offset 0, flags [none], proto UDP (17), length 44) 192.168.100.20.16403 > 17.155.127.222.16385: UDP, length 16
20:49:31.947379 IP (tos 0x0, ttl 64, id 28130, offset 0, flags [none], proto UDP (17), length 44) 192.168.100.20.16403 > 17.155.127.223.16386: UDP, length 16
20:49:32.001999 IP (tos 0x0, ttl 55, id 0, offset 65376, flags [+], proto UDP (17), length 44, bad cksum 8d8b (->8d9f)!) 17.155.127.222 > 192.168.100.20: udp
20:49:32.003186 IP (tos 0x0, ttl 54, id 0, offset 65376, flags [+], proto UDP (17), length 44, bad cksum 8e8a (->8e9e)!) 17.155.127.223 > 192.168.100.20: udp
20:49:32.003295 IP (tos 0x0, ttl 55, id 0, offset 65376, flags [+], proto UDP (17), length 44, bad cksum 8d8b (->8d9f)!) 17.155.127.222 > 192.168.100.20: udp