Function SafeResultRange.isValid
Check whether the range can still be used, or has been invalidated.
bool isValid() pure nothrow @property @safe const;
A SafeResultRange becomes invalidated (and thus cannot be used) when the
server is sent another command on the same connection. When an invalidated
SafeResultRange is used, a MYXInvalidatedRange is
thrown. If you need to send the server another command, but still access
these results afterwords, you can save the results for later by converting
this range to an array via
std.