GetHashCode is used to file an object in a Dictionary or Hashtable. If GetHashCode uses
non-readonly fields and those fields change after the object is stored, the object immediately becomes mis-filed in the
Hashtable. Any subsequent test to see if the object is in the Hashtable will return a false negative.
Exceptions
This rule does not raise if the type implementing GetHashCode is a value type, for example a struct or a record
struct, since when a value type is stored in a Dictionary or Hashtable, a copy of the value is stored, not a
reference to the value.
