public void checkLastTagWas(final int value) throws ProtobufException
    {
        if (lastTag != value)
        {
            throw ProtobufException.invalidEndTag();
        }
    }
Verifies that the last call to readTag() returned the given tag value. This is used to verify that a nested group
ended with the correct end tag.

@throws ProtobufException
            {@code value} does not match the last tag.
protostuff-core/src/main/java/io/protostuff/ByteArrayInput.java