MicrosoftExtensionsLogging: Add each log argument/attribute to the context data

[tylerohlsen]

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Feature Description

Currently, with MEL, only log scopes are included in the context data (using logger.BeginScope(...)). The log attributes that are passed as arguments to the standard logger.Log* methods are not in the context data. They are included in the formatted message, but then they lose a lot of value because they need to be parsed back out during ingestion.

For example, explicit calls to the logger (or logger extension methods) like this do not have MyData as a context data value:

logger.LogInformation("My log message with some data: {MyData}", myData);

or via the Source Generator (generated) calls like this do not have the RouteData, MethodInfo, etc as context data values:

[LoggerMessage(102, LogLevel.Information, "Route matched with {RouteData}. Executing controller action with signature {MethodInfo} on controller {Controller} ({AssemblyName}).", EventName = "ControllerActionExecuting", SkipEnabledCheck = true)]
private static partial void ControllerActionExecuting(ILogger logger, string routeData, MethodInfo methodInfo, string controller, string? assemblyName);

Describe Alternatives

None considered

Additional context

I believe this already works as described with other loggers (e.g. Serilog and NLog), but I could be wrong.

Priority

Really Want