OperationContext creation avoid sync-over-async

[joostas]

Description

Enhances OperationContext creation.

Currently OperationContext is created using constructor. This prevents executing async code. But during construction of OperationContext there is a need to execute an asynchronous operation to read request content

await message.Content.ReadAsByteArrayAsync();

This requires to fallback to sync-over-async anti-pattern in OperationContext constructor:

SetContentAsync(message).GetAwaiter().GetResult();

This change introduces static asynchronous factory methods to create OperationContext:

public static async Task<OperationContext> CreateAsync(HttpRequestMessage message);
public static async Task<OperationContext> CreateAsync(HttpRequestMessage message, IHttpCustomHeaderCollection headers);

They are used through the codebase to create OperationContext instances:

 _context = await OperationContext.CreateAsync(request, _headers);

Additional notes:

Needed to add this exception to the rule to be able to build the solution.

<WarningsNotAsErrors>NU1903</WarningsNotAsErrors> <!-- To be able to restore Microsoft.Extensions.Caching.Memory -->

Didn't want to update the version of this dependency, because I think this is out of the current improvement scope.

Related issues

Addresses issue #140.

Testing

Added WebPipeline test that emulates long-running request message content reading (that allows to kick-in scenario described in issue #140)

Reviewer Checklist

• Update the title of the PR to be succinct and less than 50 characters
• Tag the PR with the type of update: Bug, New-Sample, Enhancement, or New-Feature
• CI is green before merge

[joostas]

@microsoft-github-policy-service agree