ServiceKeyLookupMode
Specifies how to look up the service key for a parameter.
ExplicitKey = 2
The key is explicitly specified.
InheritKey = 0
The key is inherited from the parent service.
NullKey = 1
A null key indicates that the parameter should be resolved from unkeyed services.
This is useful for DI implementations that require an explicit way to declare that the parameter should be resolved from unkeyed services.