Represents the arithmetic and other operations for an operand type.
Most operations are implemented as fields that contain delegates
that perform the operation. This gives the best performance.
When an operation can have several overloads,
methods that wrap private fields are used instead.
For primitive types, the operation is performed directly if it is defined.
For other types, operator methods are used if they are available.
Otherwise, if an arithmetic type has been declared for the operand type
in the type association registry, the operations defined by that
arithmetic type are used.