[API review] IMemoryPoolFactory options

[JamesNK]

Background and Motivation

IMemoryPoolFactory<T> was added in #61003.

This issue proposes a small change to support options when creating a memory pool. Initially options will only be used to pass the owner of the factory, which is used in diagnostics.

The owner in telemetry allows memory pools used by different servers (iis, httpsys, kestrel) or libraries to be viewed separately when there are multiple memory pools in the same app.

In the future more options could be passed (eviction options like timer frequency?) but none are planned for now.

Proposed API

namespace Microsoft.AspNetCore.Connections;

public interface IMemoryPoolFactory<T>
{
-    MemoryPool<T> Create();
+    MemoryPool<T> Create(MemoryPoolOptions? options = null);
}

+ public class MemoryPoolOptions
+ {
+     public string? Owner { get; set; }
+ }

Usage Examples

public class MyType(IMemoryPoolFactory<byte> memoryPoolFactory)
{
    private readonly MemoryPool<byte> _pool = memoryPoolFactory.Create(new { Owner = "contoso" });
}

Alternative Designs

• MemoryPool<T> Create(MemoryPoolOptions? options = null) parameter is optional. Decided to use optional parameter to avoid users having to pass empty options.
• MemoryPoolOptions is no sealed in case factory implementions want to extend it with new values.

Risks

[dotnet-policy-service]

Thank you for submitting this for API review. This will be reviewed by @dotnet/aspnet-api-review at the next meeting of the ASP.NET Core API Review group. Please ensure you take a look at the API review process documentation and ensure that:

• The PR contains changes to the reference-assembly that describe the API change. Or, you have included a snippet of reference-assembly-style code that illustrates the API change.
• The PR describes the impact to users, both positive (useful new APIs) and negative (breaking changes).
• Someone is assigned to "champion" this change in the meeting, and they understand the impact and design of the change.

[MihuBot]

Possible related and/or duplicate issues:

• [API Proposal]: PinnedBlockMemoryPool metrics #61594
• Server memory pool metrics updates #63032

[halter73]

What about calling MemoryPoolOptions MemoryPoolCreationOptions instead? It might be better if we ever have global not-per-create options that we inject using IOptions<MemoryPoolOptions>.

[JamesNK]

If there were global options then they'd be injected into the factory, and likely be called MemoryPoolFactoryOptions.