int inputOffsetField = inputCount > 0 ? payloadStart : 0;
        int outputOffsetField = outputCount > 0 ? payloadStart + inputCount : 0;

        // inputOffset (relative to header start)
        SMBUtil.writeInt4(inputOffsetField, buf, pos);
        pos += 4;
        // inputCount
        SMBUtil.writeInt4(inputCount, buf, pos);
        pos += 4;