Snapstart Minimal API Performance Improvements

[ppittle]

Issue #, if available:
It is not feasible for users to warm up the asp.net and lambda pipelines via SnapshotRestore.RegisterBeforeSnapshot when using .NET MinimalAPI Lambda.

Description of changes:
Creates a new extension method, AddAWSLambdaBeforeSnapshotRequest that allows users to add a function meant to initialize the asp.net and lambda pipelines during SnapshotRestore.RegisterBeforeSnapshot, improving the performance gains offered by SnapStart.

Example:

var builder = WebApplication.CreateSlimBuilder(args);

builder.Services.AddAWSLambdaHosting(LambdaEventSource.HttpApi);

// Initialize asp.net pipeline before Snapshot
builder.Services.AddAWSLambdaBeforeSnapshotRequest(async httpClient =>
{
     await httpClient.GetAsync($"/test");
});

var app = builder.Build();
 
app.MapGet($"/test", () => "Success");
 
app.Run();

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[philasmar]

Ran the AWS CI PR check manually https://github.com/aws/aws-lambda-dotnet/actions/runs/13835574482/job/38709627134

[normj]

My reading is there are 2 different solutions being implemented here. One for AspNetCoreServer.Hosting and one for just using AspNetCoreServer. I would rather we not have different solutions and it seems like the subclasses in AspNetCoreServer.Hosting could override the virtual method for getting the list or requests to run and the service collection extension method could provide a way to get the request into that collection returned in the override.

Plus if you do it that way you can remove any changes you did to RuntimeSupport.

[ppittle]

My reading is there are 2 different solutions being implemented here. One for AspNetCoreServer.Hosting and one for just using AspNetCoreServer. I would rather we not have different solutions and it seems like the subclasses in AspNetCoreServer.Hosting could override the virtual method for getting the list or requests to run and the service collection extension method could provide a way to get the request into that collection returned in the override.

Plus if you do it that way you can remove any changes you did to RuntimeSupport.

I have unified the 2 approaches so now AspNetCoreServer.Hosting uses the virtual method in AbstractAspNetCoreFunction as you suggested.