in (child.isHidden || child.layout.expand <= denominator, format!"Nodes %s/%s sizes are out of date, call updateSize after updating the tree or layout (%s/%s)"(typeid (this), typeid (child), child.layout.expand, denominator))
out (r; [r.tupleof].all!isFinite, format!"space: child %s given invalid size %s. available = %s, expand = %s, denominator = %s, reserved = %s"(typeid (child), r, available, child.layout.expand, denominator, reservedSpace))
Get space for a child.