* Make AdobeFontMetricsLigature a struct
* Make AdobeFontMetricsCharacterSize a struct
* Eliminate allocation in CompactFontFormatData
* Pass TransformationMatrix by reference
* Seal Encoding classes
* Make SubTableHeaderEntry a readonly struct
* Introduce StringSplitter and eliminate various allocations in GlyphListFactory
* Eliminate a few substring allocations
* Use char overload on StringBuilder
* Eliminate virtual calls on stringIndex
* Optimize ReadHelper ReadLong and ReadInt methods
* Add additional readonly annotations to PdfRectangle
* Optimize NameTokenizer
* Eliminate allocation in TrueTypeGlyphTableSubsetter
* Use empty arrays
* Eliminate allocations in OperationWriteHelper.WriteHex
* Use simplified DecryptCbc method on .NET 6+
* Fix windows-1252 encoding not working on net6.0 and 8.0
* Update int buffers to exact unsigned max length and eliminate additional byte allocation
* Fix typo
* Remove unused constant
