Add Stream overrides for reading/writing spans to MemoryStream<TOwner>

[bill-poole]

Overview

The Stream class has default virtual methods for reading/writing Span<T>/ReadOnlySpan<T> and Memory<T>/ReadOnlyMemory<T> that are very inefficient because they were added when Span<T>/ReadOnlySpan<T> and Memory<T>/ReadOnlyMemory<T> were added in .NET Core 2.1. These default methods allocate an array from the array pool, copy data into the array and then invoke the byte[] variant of the read/write method.

The MemoryStream<TOwner> class should be updated to override the Span<T>/ReadOnlySpan<T> and Memory<T>/ReadOnlyMemory<T> variants of the read/write methods to avoid this unnecessary overhead.

API breakdown

namespace CommunityToolkit.HighPerformance.Streams;

internal partial class MemoryStream<TSource> : Stream
    where TSource : struct, ISpanOwner
{
    public override int Read(Span<byte> buffer);

    public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default);

    public override void Write(ReadOnlySpan<byte> buffer);

    public override ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = default);
}

Usage example

These are standard Stream methods that should be overridden. Standard usage for these methods.

Breaking change?

No

Alternatives

No alternatives.

Additional context

No response

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