CA2217: Do not mark enums with FlagsAttribute
An externally visible enumeration is marked with FlagsAttribute and it has one or more values that are not powers of two or a combination of the other defined values on the enumeration.
An enumeration should have FlagsAttribute present only if each value defined in the enumeration is a power of two, or a combination of defined values.
The following example shows an enumeration, Color, that contains the value 3, which is neither a power of two, nor a combination of any of the defined values. The Color enumeration should not be marked with the FlagsAttribute.
The following example shows an enumeration, Days, that meets the requirements for being marked with the System.FlagsAttribute.