Make Boxed Queries Cloneable

[Narfinger]

At the moment Boxed Queries (resulting from into_boxed()) are not cloneable.
My use case is that I want to keep constructing the query in a different part of the code and keep it in a struct. Periodically I want to execute the query and load the result but of course, keep the struct.

Is there a reason why this is not cloneable?

[sgrif]

Clone is not object safe. We can never make them cloneable.