See http://b/issue?id=1751571 Changes the semantics of SmsHeader from containing only opaque data to exposing occurs-once frequently-used fields together with a list of opaque fields. Also changes the coding to and from byte array to be symmetrical, whereas previous encoding had an extra length field. Cdma SmsMessage -- cleanup of code paths along with adjustments to match the new header semantics, which should address at least some of the issues with concatenated messages. See http://b/issue?id=1809759