HasFlat
BMessage::HasFlat(const char *name, const BFlattenable *object) const
BMessage::HasFlat(const char *name, int32 index, const BFlattenable *object)
BMessage::HasFlat(const char* name, const BFlattenable* object) const
BMessage::HasFlat(const char* name, int32 index, const BFlattenable* object)