From Mod Wiki
string material -- Name of the materal for the icon. integer priority -- Priority for showing this icon over others. float timeout -- Timeout in seconds, less that or equal to 0 is no timeout.
- If the material is invalid, the result will be -1.
- See also freeIcon.
- If you supply a timeout, you should not try and free the icon manually.
Allocates a player icon, and returns a handle to it.