<PackageReference Include="System.Diagnostics.DiagnosticSource" Version="6.0.2" />

SampleActivity<T>

public sealed delegate SampleActivity<T> : MulticastDelegate
Define the callback that can be used in ActivityListener to allow deciding to create the Activity objects and with what data state.
using System.Runtime.CompilerServices; namespace System.Diagnostics { public delegate ActivitySamplingResult SampleActivity<[System.Runtime.CompilerServices.Nullable(2)] T> ([System.Runtime.CompilerServices.Nullable(new byte[] { 0, 1 })] ref ActivityCreationOptions<T> options); }