Add @NonNull and @Nullable annotations in NetlinkMessage.

Add @NonNull and @Nullable annotations on StructNlMsgHdr and parse
function to give the caller a clear indication the StructNlMsgHdr
should be non-null and safe to call its public method, avoid throwing
NPE; the same for parse code, which might return null and caller
should check the nullability of return value.

Bug: 163492391
Test: atest NetworkStaticLibsTests
Change-Id: I0cdf6e611a2b5398b048ffc02ec8fb5f8f8a73db
7 files changed
tree: c029287463ea46d2ae93bdf113ff96bb75cee0db
  1. staticlibs/