a dns :query() doesn't close socket on timeout

[daurnimator]

If a query times out it doesn't close the socket. For UDP I think this is expected, but not so much for TCP:

local dns_record = require "cqueues.dns.record"
local dns_resolvers = require "cqueues.dns.resolvers"
local dns_config = require "cqueues.dns.config"

local pool = dns_resolvers.new(dns_config.stub{
	nameserver = { "8.8.8.8" };
	tcp = dns_config.TCP_ONLY;
})
local ans, errno = pool:query("google.com", dns_record.A, dns_record.IN, 0.0001)
print(ans, errno) --> nil, ETIMEDOUT
-- socket gets left open but can't be reused.