This package is only required in the classic App Engine environment.
Applications running only in App Engine "flexible environment" should
use the standard library's net package.
Dial connects to the address addr on the network protocol.
The address format is host:port, where host may be a hostname or an IP address.
Known protocols are "tcp" and "udp".
The returned connection satisfies net.Conn, and is valid while ctx is valid;
if the connection is to be used after ctx becomes invalid, invoke SetContext
with the new context.
SetContext sets the context that is used by this Conn.
It is usually used only when using a Conn that was created in a different context,
such as when a connection is created during a warmup request but used while
servicing a user request.