<PackageReference Include="OpenTelemetry" Version="1.16.0-rc.1" />

Microsoft.Extensions.Options.DelegatingOptionsFactory<TOptions>

sealed class DelegatingOptionsFactory<TOptions> : OptionsFactory<TOptions>
An OptionsFactory<T> that creates options instances via a caller-supplied delegate, rather than CreateInstance<T>. The delegate receives the IConfiguration registered in the DI container, allowing options constructors to read environment variables and configuration keys before any IConfigureOptions<T> delegates run. This establishes the SDK priority model: Factory delegate - env var / IConfiguration defaults. IConfigureOptions<T> (Configure<T>) - programmatic overrides. IPostConfigureOptions<T> (PostConfigure<T>) - post-configuration. IValidateOptions<T> - validation gate.
public DelegatingOptionsFactory(Func<IConfiguration, string, TOptions> optionsFactoryFunc, IConfiguration configuration, IEnumerable<IConfigureOptions<TOptions>> setups, IEnumerable<IPostConfigureOptions<TOptions>> postConfigures, IEnumerable<IValidateOptions<TOptions>> validations)

Initializes a new instance of the DelegatingOptionsFactory<T> class.