Hello and thanks for the good work on this library.

While I was using it I came across one inconsistency with respect to handling x5c certificates on various asymmetric keys. It looks that in principle

will store the x5c on the key instance but only for RSAKeys this is also included in serialize().

Is this intentional? In principal I see no problem, that also other asymmetric keys could have a x5c certificate attached to it, in particular the ECKey.
Would you consider this a reasonable change?