containerd: add comment to properties
make clear why we need to construct the filters in a particular way.
@@ -9,6 +9,18 @@ import (
// propertiesToFilterList converts a set of garden properties to a list of
// filters as expected by containerd.
//
+// containerd filters are in the form of
+//
+// <what>.<field><operator><value>
+//
+// which, in our very specific case of properties, means
+//
+// labels.foo==bar
+// | | | value
+// | | equality
+// | key
+// what
+//
func propertiesToFilterList(properties garden.Properties) (filters []string, err error) {
filters = make([]string, len(properties))
