def deps do
  [
    {:happy_tcp, github: "ruslandoga/happy_tcp"}
  ]
end

iex> default_tcp_module = :inet_db.tcp_module()
#==> :inet_tcp
iex> :inet_db.set_tcp_module(:happy_tcp)
#==> :ok

# try out some of the hosts from http:https://dual.tlund.se

# try ipv4-only host (has only A records)
iex> {:ok, socket} = :gen_tcp.connect(~c"ipv4.tlund.se", 80, active: false)
#==> {:ok, #Port<0.666>}
iex> :inet.peername(socket)
#==> {:ok, {{193, 15, 228, 195}, 80}}
iex> :gen_tcp.close(socket)
#==> :ok

# now try ipv6-only host (has only AAAA recods)
#
# note that this one would only work if you have ipv6 connection to the internet
# you can check it with some other tool like ping6
#
#     $ ping6 ipv6.tlund.se
#
iex> {:ok, socket} = :gen_tcp.connect(~c"ipv6.tlund.se", 80, active: false)
#==> {:ok, #Port<0.666>}
#===> or {:error, :ehostunreach} if you don't have IPv6
iex> :inet.peername(socket)
#==> {:ok, {{10752, 2049, 15, 0, 0, 0, 0, 405}, 80}}
iex> :gen_tcp.close(socket)
#==> :ok

# now try dual-stack host (has both A and AAAA records)
#
# this should prefer ipv6 if it's avaible on your machine
iex> {:ok, socket} = :gen_tcp.connect(~c"dual.tlund.se", 80, active: false)
#==> {:ok, #Port<0.666>}
iex> :inet.peername(socket)
#==> {:ok, {{10752, 2049, 15, 0, 0, 0, 0, 405}, 80}}
#==> or {:ok, {{193, 15, 228, 195}, 80}} if you don't have IPv6
iex> :gen_tcp.close(socket)
#==> :ok

# now let's try TLS connections just in case (ensure :ssl app is loaded and started)
iex> {:ok, socket} = :ssl.connect(~c"google.com", 443, [:binary, cacerts: :public_key.cacerts_get])
#==> {:ok,
#==>  {:sslsocket, {:gen_tcp, #Port<0.666>, :tls_connection, :undefined},
#==>   [#PID<0.667.0>, #PID<0.666.0>]}}
iex> :ssl.peername(socket)
#==> {:ok, {{9220, 26624, 16387, 3074, 0, 0, 0, 101}, 443}}
#==> or {:ok, {{172, 217, 26, 78}, 443}} if you don't have IPv6
iex> :ssl.close(socket)
#==> :ok

# testing done, we can now put everything back the way it was before
iex> :inet_db.set_tcp_module(default_tcp_module)
#==> :ok

iex> :happy_tcp.getaddrs(~c"google.com")
#==> {:ok,
#==>  [
#==>    {9220, 26624, 16387, 3074, 0, 0, 0, 139},
#==>    {74, 125, 24, 139},
#==>    {9220, 26624, 16387, 3074, 0, 0, 0, 102},
#==>    {74, 125, 24, 138},
#==>    {9220, 26624, 16387, 3074, 0, 0, 0, 100},
#==>    {74, 125, 24, 102},
#==>    {9220, 26624, 16387, 3074, 0, 0, 0, 101},
#==>    {74, 125, 24, 100},
#==>    {74, 125, 24, 113},
#==>    {74, 125, 24, 101}
#==>  ]}