Parse message with no body fields

Previously, the bodyBytes was ending up with the trailer in it when the
body contained no fields, and trailerBytes was empty

message.go

@@ -210,6 +210,7 @@ func ParseMessageWithDataDictionary(
 
 	trailerBytes := []byte{}
 	foundBody := false
+	foundTrailer := false
 	for {
 		parsedFieldBytes = &msg.fields[fieldIndex]
 		if xmlDataLen > 0 {
@@ -228,6 +229,7 @@ func ParseMessageWithDataDictionary(
 			msg.Header.add(msg.fields[fieldIndex : fieldIndex+1])
 		case isTrailerField(parsedFieldBytes.tag, transportDataDictionary):
 			msg.Trailer.add(msg.fields[fieldIndex : fieldIndex+1])
+			foundTrailer = true
 		default:
 			foundBody = true
 			trailerBytes = rawBytes
@@ -247,6 +249,12 @@ func ParseMessageWithDataDictionary(
 		fieldIndex++
 	}
 
+	// This will happen if there are no fields in the body
+	if foundTrailer && !foundBody {
+		trailerBytes = rawBytes
+		msg.bodyBytes = nil
+	}
+
 	// Body length would only be larger than trailer if fields out of order.
 	if len(msg.bodyBytes) > len(trailerBytes) {
 		msg.bodyBytes = msg.bodyBytes[:len(msg.bodyBytes)-len(trailerBytes)]