SvgFontManager fails to initialize if multiple fonts of the same name exist

[chucker]

(This may be a platform-specific quirk in .NET Standard. It's not clear to me from the description of https://docs.microsoft.com/en-us/dotnet/api/system.drawing.fontfamily.families?view=netframework-4.8 what happens if two fonts of the same name exist — it could be that this isn't possible in Windows but is in macOS.)

The type initializer in SvgFontManager creates a dictionary by font name. If names aren't unique, this will throw:

System.ArgumentException: "An item with the same key has already been added. Key: hiragino sans gb"
  at System.Collections.Generic.Dictionary`2.TryInsert(TKey key, TValue value, InsertionBehavior behavior)\n   at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value)\n   at System.Linq.Enumerable.ToDictionary[TSource,TKey](TSource[] source, Func`2 keySelector, IEqualityComparer`1 comparer)\n   at System.Linq.Enumerable.ToDictionary[TSource,TKey](IEnumerable`1 source, Func`2 keySelector, IEqualityComparer`1 comparer)\n   at System.Linq.Enumerable.ToDictionary[TSource,TKey](IEnumerable`1 source, Func`2 keySelector)\n   at Svg.SvgFontManager..cctor() in /Users/chucker/Repositories/SVG-448-netcore/Source/SvgFontManager.cs:22

This breaks the test LargeEmbeddedImageTest and possibly others on my machine.

[mrbean-bremen]

Reading up about font names, it looks as if it is allowed to have several fonts with the same name, as long as they have different weight and/or style.
As far as I understand the code, it doesn't matter if there is more than one font for a name, as the font name is only used to lookup the font family, so maybe your workaround is already sufficient to resolve this issue.

[mrbean-bremen]

Actually, this has been introduced with the recent introduction of the font manager - before that FirstOrDefault has been used. So this is probably a regression...

[mrbean-bremen]

@chucker - I think this can be closed. As I wrote, I do not consider your fix a workaround, as it shouldn't matter for the usage if there is more than one font for the name.