@Override
    public byte[] readByteArray() throws IOException
    {
        final int length = readRawVarint32();
        if (length < 0)
            throw ProtobufException.negativeSize();

        if (buffer.remaining() < length)
            // if(offset + length > limit)
            throw ProtobufException.misreportedSize();

        final byte[] copy = new byte[length];
        buffer.get(copy);
        return copy;
    }
Read an {@code sint64} field value from the internal buffer.
protostuff-core/src/main/java/io/protostuff/ByteBufferInput.java