public UnsubscribeContext(IBehaviorContext parentContext, Type eventType, UnsubscribeOptions options)
: base(parentContext)
{
Guard.AgainstNull(nameof(parentContext), parentContext);
Guard.AgainstNull(nameof(eventType), eventType);
Guard.AgainstNull(nameof(options), options);
parentContext.Extensions.Merge(options.Context);
EventType = eventType;
}