Failed to convert serialized Instant to JSON

[jabolina]

We can serialize a java.time.Instant through the WrappedMessage, where it writes an int64 and int32:

protostream/core/src/main/java/org/infinispan/protostream/WrappedMessage.java

Lines 293 to 298 in 8d20c39

	if (t instanceof Instant instant) {
	out.writeInt64(WRAPPED_INSTANT_SECONDS, instant.getEpochSecond());
	out.writeInt32(WRAPPED_INSTANT_NANOS, instant.getNano());
	out.flush();
	return;
	}

However, the conversion to JSON fails, resulting in an empty String. I see other (primitive) types work out of the box. A simple reproducer:

   @Test
   public void testInstant() throws Exception {
      ImmutableSerializationContext ctx = createContext();

      byte[] data = ProtobufUtil.toWrappedByteArray(ctx, Instant.EPOCH);
      System.out.println(ProtobufUtil.toCanonicalJSON(ctx, data));
   }

I've run this from the ProtobufUtilTest class.