Does not work with IPV6.

[nilo85]

Using this with IPV6 i get these kind of compile errors

pio/libdeps/d1_mini/ESPAsyncTCP/src/ESPAsyncTCP.cpp: In member function 'bool AsyncClient::connect(IPAddress, uint16_t)':
.pio/libdeps/d1_mini/ESPAsyncTCP/src/ESPAsyncTCP.cpp:248:8: error: 'ip_addr_t' {aka 'struct ip_addr'} has no member named 'addr'; did you mean 'u_addr'?
248 | addr.addr = ip;
| ^~~~
| u_addr
.pio/libdeps/d1_mini/ESPAsyncTCP/src/ESPAsyncTCP.cpp: In member function 'bool AsyncClient::connect(const char*, uint16_t)':

turns out this library does not understand the ip4/ip6 implementation of ESP8622 core.
https://github.com/esp8266/Arduino/blob/master/tools/sdk/lwip2/include/lwip/ip_addr.h#L69

[nilo85]

Made a draft PR that makes it compile on my machine.
#192

Not 100% sure it works as intended, ipv4 http server seems still work with this thoug, will try ipv6 soon =)