Making LookupClient and DnsMessageHandlers disposable.
Primarily to dispose the TcpClient-pool.
The pool could be empty if the TCP fallback was either disabled or never used, so it is not always necessary to dispose the LookupClient owning that resource.
Making LookupClient and DnsMessageHandlers disposable. Primarily to dispose the TcpClient-pool. The pool could be empty if the TCP fallback was either disabled or never used, so it is not always necessary to dispose the LookupClient owning that resource.