verns how the injector reuses
 instances of the type. By default, if no scope annotation is present, the
 injector creates an instance (by injecting the type's constructor), uses
 the instance for one injection, and then forgets it. If a scope annotation
 is present, the injector may retain the instance for possible reuse in a
 later injection. If multiple threads can access a scoped instance, its
 implementation should be thread safe. The implementation of the scope
 itself is left up to the injector.

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