Add support for nullable data which should not create a resource
In some cases null is a valid value to return, but should not be used to initialize a resource. For example if a DTO contains some optional resources which may never be set for some providers, but will be set for others, and those resources may be null, then this was not previously possible
Signed-off-by: Tim Ward <timothyjward@apache.org> (commit: 068be10)
