TiffEncoder: Avoid buffer2D.GetSingleSpan() and use GetPixelRowSpan instead

[brianpopow]

Prerequisites

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• I have provided test coverage for my change (where applicable)

Description

As made clear with #1660 the usage of buffer2D.GetSingleSpan() is problematic and not always guaranteed to return a complete span. This PR will change the Tiff Encoder to avoid the usage of buffer2D.GetSingleSpan() and use GetPixelRowSpan instead.

[JimBobSquarePants]

Wow! That was quick! 😍

[codecov]

Codecov Report

Merging #1662 (bcb3b7d) into master (261c868) will increase coverage by 0.01%.
The diff coverage is 96.42%.

@@            Coverage Diff             @@
##           master    #1662      +/-   ##
==========================================
+ Coverage   84.31%   84.32%   +0.01%     
==========================================
  Files         816      816              
  Lines       35824    35856      +32     
  Branches     4160     4167       +7     
==========================================
+ Hits        30204    30235      +31     
  Misses       4799     4799              
- Partials      821      822       +1     

Flag	Coverage Δ
unittests	84.32% <96.42%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ts/Tiff/Compression/Compressors/T4BitCompressor.cs	92.33% <ø> (ø)
...ormats/Tiff/Writers/TiffBaseColorWriter{TPixel}.cs	95.45% <ø> (-0.11%)	⬇️
.../Formats/Tiff/Writers/TiffPaletteWriter{TPixel}.cs	97.10% <90.90%> (-1.15%)	⬇️
.../Formats/Tiff/Writers/TiffBiColorWriter{TPixel}.cs	95.74% <100.00%> (+1.62%)	⬆️
...s/Tiff/Writers/TiffCompositeColorWriter{TPixel}.cs	94.73% <100.00%> (+3.82%)	⬆️

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[IldarKhayrutdinov]

@brianpopow @JimBobSquarePants @antonfirsov sorry, I'm a distracted, great work @brianpopow 👍

[JimBobSquarePants]

No worries @IldarKhayrutdinov we move fast! 😀