Use Array.Empty<> over Enumerable.Empty<>

[MikeAlhayek]

No description provided.

[kevinchalet]

Don't expect any noticeable perf' improvement (because well, Enumerable.Empty<TResult>() calls Array.Empty<T> internally 🤣), but it's a good opportunity to simplify the syntax by using [] instead of Enumerable.Empty<TResult>()/Array.Empty`.

[MikeAlhayek]

@kevinchalet yes there is no advantage. just once less call :)

Also, I think [] is different than Array.Empty<>. Array.Empty<> returns the same instance every time whereas [] creates a new instances every time.

[kevinchalet]

Also, I think [] is different than Array.Empty<>. Array.Empty<> returns the same instance every time whereas [] creates a new instances every time.

Nope: https://sharplab.io/#v2:CYLg1APgAgTAjAWAFBQMwAJboMLoN7LpGYZQAs6AsgBQCU+hxTUcADANoC66AhgE58eAT3QBedFwDcjIgF9ksoA= 😄

[MikeAlhayek]

@kevinchalet that's awesome! and change it to a mutable object like a list autmatically create new List! thanks for the tip!

[kevinchalet]

@kevinchalet that's awesome! and change it to a mutable object like a list autmatically create new List! thanks for the tip!

Yeah! And it uses CollectionsMarshal.AsSpan() to populate the list so it's very efficient 😄

Note: you can even use the range operator to build collections! E.g: https://github.com/openiddict/openiddict-core/blob/fb2565e298223940de7cf5e1c2fb3dd8de5bc516/src/OpenIddict.Client/OpenIddictClientHandlers.cs#L25-L162

[MikeAlhayek]

Making this change part of #15187. closing this one.