Use this class when the K and V are not Any, however it cannot be used to initialize itself
A codec for packing and unpacking to and from Any values.
A codec for packing and unpacking to and from Any values. NOTE: it has to be defined like this so that we can create default objects which refer to themselves as the base K and V codecs
MUST USE def's in trait initialization otherwise you end up with nasty NPEs
Codecs to read any value. For Longs it is slightly different than the LongCodec because a UINT64 can return a BigInt when the value is greater than Long.MaxValue