Indicates the element type of the UnmanagedType.SafeArray.
You can set this field to a value from the System.Runtime.InteropServices.VarEnum enumeration to specify the type of the safe array's elements. If a type is not specified, the managed element type's default type (if passed as a VARIANT) is used. For example, the SafeArraySubType for an int array in COM is VarEnum.VT_I4. For additional information, see [<topic://cpcondefaultmarshalingforarrays>].