Since we can't directly depend on proto headers, we rely on ADL + proto headers being included by calling code for this matcher to choose the right overload of `DynamicCastMessage`.
PiperOrigin-RevId: 940593408
Change-Id: I7374aed3c5cfe61a183d28ea02e6583ab340f647
Protobuf messages have a custom dynamic_cast, for when RTTI is not available on the messages.
PiperOrigin-RevId: 933270097
Change-Id: Iaeb50bce3fe1b746306a7507ab1985b111c03416