Represents the parts of WireIdentity that are specific to a X509 certificate (and not a Basic one).
X509 certificate identifying this client in the MLS group ; PEM encoded
Name as displayed in the messaging application e.g. John Fitzgerald Kennedy
John Fitzgerald Kennedy
DNS domain for which this identity proof was generated e.g. whitehouse.gov
whitehouse.gov
user handle e.g. john_wire
john_wire
X509 certificate not after as Unix timestamp
X509 certificate not before as Unix timestamp
X509 certificate serial number