In the message class hierarchy, methods of response is specified by subclasses, whereas response code ranges (i.e. 1xx, 2xx, etc) are specified by interfaces. Thus there are InviteResponse, ByeResponse etc as classes, and SuccessResponse, ErrorResponse etc as interfaces.
RedirectResponse is inconsistent with this scheme. Currently, RedirectResponse is a class and is used for 3xx responses to INVITE.
Suggest change RedirectResponse to interface, and add InviteRedirectResponse, InviteRedirectResponse300, etc classes.
See 3304036