Signature field for SRB_IO_CONTROL structure

I am trying to send an IOCTL command using IOCTL_SCSI_MINIPORT control function.
When I setup the header using the SRB_IO_CONTROL structure, what should be set in signature field?

Thanks.

The value used in the SRB_IO_CONTROL’s signature field is defined by each HBA vendor and validated by the vendor-specific miniport driver.

Typically this value is the filename of the miniport driver. However, this is a curious question to come up because this IOCTL and SCSI miniports should not need to be developed anymore.