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  • Yu Sasaki thinks this is interesting:

There are general rules to guarantee that each object gets a unique hashing algorithm:

Objects that compare as equal must return the same hashed value.

GetHashCode() must return the same value every time, unless the internal value or state is modified.

The hashed value is not like a GUID (global unique identifier) in that it is not globally unique, but only unique if the hashed ...

From

Cover of Design Patterns

Note

GetHashCode() rules