1.0.0

U8Abstractions (definition)
- Comparison
- Case conversion
- Splitting
- Enumeration
- Allocation (internal, not for 1.0.0)
U8String
- CoreLib string non-globalization features parity
  - Split
  - Slice
  - Replace, Remove
  - Enumerations
  - Conversions
  - Concat, Join
  - Comparison, Equality and Hashcode
  - Format
  - Trim
  - etc.
- Comparison
  - Ordinal
  - AsciiIgnoreCase
  - ~~OrdinalIgnoreCase~~
  - ~~FallbackInvariant~~
  - ~~FallbackInvariantIgnoreCase (?)~~
- Case conversion
  - Ascii
  - ~~FallbackInvariant~~
- Unsafe (U8Marshal)
Extensions
- HttpClient (basic variants)
- ~~Stream~~ and SafeHandle (basic variants)
- Console (?)
U8Info, U8Scalar

1.1.0

ICU/NLS-dependent features
- U8OrdinalIgnoreCaseComparer
- U8OrdinalCaseConverter
- U8InvariantCaseConverter
- IsNormalized/Normalize(NormalizationForm)
NativeU8String (1.X.X candidate?)
- NativeU8Span (?)
SearchValues<U8String> + method overloads that accept it
Stream enhancements (bespoke validating stream reader?)
- ReadLine/Async
Extending existing methods
- Replace(..., T comparer), ReplaceAny (both variants)
- Remove(..., T comparer), RemoveAny (both variants)
- SplitAny(..., T comparer)