by [email protected]:

I have seen the issue in 1.0.3 and from checking tip.golang.org, it is still a problem.

net.errClosing is an errors.New() that is not exported but returned to the user. This
means that in order for a user to check for the "errClosing", they need to
check the error string.

I suggest renaming to ErrClosing so that a client can easily check if another goroutine
closed it's connection.