fully support UDP

[Xmader]

merge code from Outline

[iMrDJAi]

Is that for UDP associate? actually it won't work.
I been testing it, the UDP associate will only work if you disable the UDP relay and the transparent DNS (See this comment by @bemasc ambrop72/badvpn#71 (comment)):

cordova-plugin-tun2socks/android/java/org/uproxy/tun2socks/Tunnel.java

Line 205 in ab12b21

socksServerAddress, // The UDP relay has the same address and port as the SOCKS server.

cordova-plugin-tun2socks/android/java/org/uproxy/tun2socks/Tunnel.java

Line 207 in ab12b21

true /* transparent DNS */,

Just like that:

    startTun2Socks(
        tunFd,
        VPN_INTERFACE_MTU,
        mPrivateAddress.mRouter,
        VPN_INTERFACE_NETMASK,
        VPN_IPV6_NULL,
        socksServerAddress,
-       socksServerAddress,  // The UDP relay has the same address and port as the SOCKS server.
+       null,
        String.format("%s:%d", DNS_RESOLVER_IP, DNS_RESOLVER_PORT),
-       true /* transparent DNS */,
+       false,
        true /* socks5 UDP Enabled */);

[iMrDJAi]

I have published a working version that supports SOCKS v5 UDP associate based on your implementation:
https://github.com/iMrDJAi/cordova-plugin-tun2socks-udp-associate

Thank you!