refactor!: remove Span<T>.Split

CHANGELOG.md

@@ -5,7 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## 4.0.0 - [Unreleased]
+## 4.0.1 - [Unreleased]
+
+### Removed
+
+- X10D: Removed `Span<T>.Split` for .NET 9.0 target due to conflicts with
+[`System.MemoryExtensions.Split`](https://learn.microsoft.com/en-us/dotnet/api/system.memoryextensions.split?view=net-8.0).
+
+## [4.0.0] - 2024-06-12
 
 ### Added
 
@@ -642,7 +649,8 @@ please [open an issue](https://github.com/oliverbooth/X10D/issues)!
 
 Earlier versions of this package are undocumented and unlisted from package results.
 
-[unreleased]: https://github.com/oliverbooth/X10D/compare/v3.3.1...main
+[unreleased]: https://github.com/oliverbooth/X10D/compare/v4.0.0...main
+[4.0.0]: https://github.com/oliverbooth/X10D/releases/tag/v4.0.0
 [3.3.1]: https://github.com/oliverbooth/X10D/releases/tag/v3.3.1
 [3.3.0]: https://github.com/oliverbooth/X10D/releases/tag/v3.3.0
 [3.2.2]: https://github.com/oliverbooth/X10D/releases/tag/v3.2.2

X10D.Tests/src/Collections/SpanTest.cs

@@ -1,5 +1,7 @@
 using NUnit.Framework;
+#if !NET9_0_OR_GREATER
 using X10D.Collections;
+#endif
 
 namespace X10D.Tests.Collections;
 
@@ -70,6 +72,7 @@ internal class SpanTest
         Assert.That(span.ToArray(), Is.EqualTo(new[] {1, 2, 3, 2, 5, 2, 7, 2, 9, 2, 11, 2, 13, 2, 15, 2}));
     }
 
+#if !NET9_0_OR_GREATER
     [Test]
     public void Split_OnEmptySpan_ShouldYieldNothing_UsingCharDelimiter_GivenReadOnlySpan()
     {
@@ -497,4 +500,5 @@ internal class SpanTest
 
         Assert.That(index, Is.EqualTo(3));
     }
+#endif
 }

X10D/src/Collections/SpanExtensions.cs

@@ -75,6 +75,7 @@ public static class SpanExtensions
     }
 #endif
 
+#if !NET9_0_OR_GREATER
     /// <summary>
     ///     Splits a span of elements into sub-spans based on a delimiting element.
     /// </summary>
@@ -134,4 +135,5 @@ public static class SpanExtensions
     {
         return new SpanSplitEnumerator<T>(source, delimiter);
     }
+#endif
 }