Add [MethodImpl(MethodImplOptions.NoInlining] to all our instrumented APIs in Datadog.Trace.Manual (#7302)

## Summary of changes

Adds `[MethodImpl(MethodImplOptions.NoInlining]` to avoid race
conditions on app startup

## Reason for change

There’s essentially a race condition with how the .NET runtime profiling
APIs work and how we inject into a customer’s application. We typically
inject into the start of the `Main()` method, and then request ReJIT for
all the methods that we want to instrument. The next time a target
method is called, the runtime will see the ReJIT request, and add our
instrumentation.

Another aspect is inlining; if a method that we wanted to instrument has
been inlined into the caller, then just doing a ReJIT won't work
(because the method is "gone" in this case). We work around that for
normally by blocking inlining for methods that we’re interested in (i.e.
methods we instrument). However, if the method we’re interested in has
_already_ been inlined _before_ we are injected then we could miss calls
at the start of the app.

Essentially there's a race condition between:
- Calls in `Main()` being JITed (and inlined).
- Our startup hook being injected and processing the instrumentation
list to block inlining for methods we care about.

We currently can't do much about this for arbitrary target methods (we
have some ideas, but that's a separate issue!) but for our manual APIs
we know we _will_ want to mark them as not-inlined. So we can
essentially pre-emptively mark these APIs with
`[MethodImpl(MethodImplOptions.NoInlining]`, exculding these methods
from the race condition (theoretically; it's technically up to the JIT
if it chooses to honour the attributes IIRC)

## Implementation details

- Add `[MethodImpl(MethodImplOptions.NoInlining]` to all the methods
marked with `[Instrumented]`
- This is a bit ugly for properties because they need to be applied to
the getter/setter, not the property
  - For consistency, moved the `[Instrumented]` attribute there too

## Test coverage

Updated the unit test to ensure that every instrumented method is
explicitly marked as `NoInlining`. Confirmed that this catches issues if
you miss one

## Other details
<!-- Fixes #{issue} -->

<!-- ⚠️ Note: where possible, please obtain 2 approvals prior to
merging. Unless CODEOWNERS specifies otherwise, for external teams it is
typically best to have one review from a team member, and one review
from apm-dotnet. Trivial changes do not require 2 reviews. -->

Author: andrewlock

tracer/src/Datadog.Trace.Manual/AppSec/EventTrackingSdk.cs

@@ -5,6 +5,7 @@
 
 #nullable enable
 
+using System.Runtime.CompilerServices;
 using Datadog.Trace.SourceGenerators;
 
 namespace Datadog.Trace.AppSec;
@@ -19,6 +20,7 @@ public static class EventTrackingSdk
     /// </summary>
     /// <param name="userId">The userId associated with the login success</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void TrackUserLoginSuccessEvent(string userId)
     {
     }
@@ -29,6 +31,7 @@ public static void TrackUserLoginSuccessEvent(string userId)
     /// <param name="userId">The userId associated with the login success</param>
     /// <param name="metadata">Metadata associated with the login success</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void TrackUserLoginSuccessEvent(string userId, IDictionary<string, string> metadata)
     {
     }
@@ -39,6 +42,7 @@ public static void TrackUserLoginSuccessEvent(string userId, IDictionary<string,
     /// <param name="userId">The userId associated with the login failure</param>
     /// <param name="exists">If the userId associated with the login failure exists</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void TrackUserLoginFailureEvent(string userId, bool exists)
     {
     }
@@ -50,6 +54,7 @@ public static void TrackUserLoginFailureEvent(string userId, bool exists)
     /// <param name="exists">If the userId associated with the login failure exists</param>
     /// <param name="metadata">Metadata associated with the login failure</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void TrackUserLoginFailureEvent(string userId, bool exists, IDictionary<string, string> metadata)
     {
     }
@@ -59,6 +64,7 @@ public static void TrackUserLoginFailureEvent(string userId, bool exists, IDicti
     /// </summary>
     /// <param name="eventName">the name of the event to be tracked</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void TrackCustomEvent(string eventName)
     {
     }
@@ -69,6 +75,7 @@ public static void TrackCustomEvent(string eventName)
     /// <param name="eventName">the name of the event to be tracked</param>
     /// <param name="metadata">Metadata associated with the custom event</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void TrackCustomEvent(string eventName, IDictionary<string, string> metadata)
     {
     }

tracer/src/Datadog.Trace.Manual/AppSec/EventTrackingSdkV2.cs

@@ -4,6 +4,7 @@
 // </copyright>
 
 #nullable enable
+using System.Runtime.CompilerServices;
 using Datadog.Trace.SourceGenerators;
 
 namespace Datadog.Trace.AppSec;
@@ -21,6 +22,7 @@ public static class EventTrackingSdkV2
     /// <param name="userId">The optional userId associated with the login success</param>
     /// <param name="metadata">The optional metadata associated with the login success</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void TrackUserLoginSuccess(string userLogin, string? userId = null, IDictionary<string, string>? metadata = null)
     {
     }
@@ -32,6 +34,7 @@ public static void TrackUserLoginSuccess(string userLogin, string? userId = null
     /// <param name="userDetails">The optional userDetails associated with the login success</param>
     /// <param name="metadata">The optional metadata associated with the login success</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void TrackUserLoginSuccess(string userLogin, UserDetails userDetails, IDictionary<string, string>? metadata = null)
     {
     }
@@ -44,6 +47,7 @@ public static void TrackUserLoginSuccess(string userLogin, UserDetails userDetai
     /// <param name="userId">The optional userId associated with the login success</param>
     /// <param name="metadata">Metadata associated with the login failure</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void TrackUserLoginFailure(string userLogin, bool exists, string? userId = null, IDictionary<string, string>? metadata = null)
     {
     }
@@ -56,6 +60,7 @@ public static void TrackUserLoginFailure(string userLogin, bool exists, string?
     /// <param name="userDetails">The details of the user associated with the login failure</param>
     /// <param name="metadata">Metadata associated with the login failure</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void TrackUserLoginFailure(string userLogin, bool exists, UserDetails userDetails, IDictionary<string, string>? metadata = null)
     {
     }

tracer/src/Datadog.Trace.Manual/Baggage.cs

@@ -4,6 +4,7 @@
 // </copyright>
 
 using System.Collections;
+using System.Runtime.CompilerServices;
 using Datadog.Trace.SourceGenerators;
 
 namespace Datadog.Trace;
@@ -19,15 +20,18 @@ public static class Baggage
     /// <summary>
     /// Gets or sets the baggage collection for the current execution context.
     /// </summary>
-    [Instrumented]
     public static IDictionary<string, string?> Current
     {
+        [Instrumented]
+        [MethodImpl(MethodImplOptions.NoInlining)]
         get
         {
             // auto-instrumentation will return Trace.Baggage.Current instead
             return _current ??= new Dictionary<string, string?>();
         }
 
+        [Instrumented]
+        [MethodImpl(MethodImplOptions.NoInlining)]
         set
         {
             // auto-instrumentation will add:

tracer/src/Datadog.Trace.Manual/Ci/TestExtensions.cs

@@ -3,6 +3,7 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
 // </copyright>
 
+using System.Runtime.CompilerServices;
 using Datadog.Trace.SourceGenerators;
 
 namespace Datadog.Trace.Ci;
@@ -18,6 +19,7 @@ public static class TestExtensions
     /// <param name="test">The <see cref="ITest"/> instance to augment</param>
     /// <param name="parameters">TestParameters instance</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void SetParameters(this ITest test, TestParameters parameters)
     {
     }
@@ -29,6 +31,7 @@ public static void SetParameters(this ITest test, TestParameters parameters)
     /// <param name="hostInfo">Host info</param>
     /// <param name="jobInfo">Job info</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void SetBenchmarkMetadata(this ITest test, in BenchmarkHostInfo hostInfo, in BenchmarkJobInfo jobInfo)
     {
     }
@@ -41,6 +44,7 @@ public static void SetBenchmarkMetadata(this ITest test, in BenchmarkHostInfo ho
     /// <param name="info">Measure info</param>
     /// <param name="statistics">Statistics values</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void AddBenchmarkData(this ITest test, BenchmarkMeasureType measureType, string info, in BenchmarkDiscreteStats statistics)
     {
     }

tracer/src/Datadog.Trace.Manual/Ci/TestModule.cs

@@ -4,6 +4,7 @@
 // </copyright>
 #nullable enable
 
+using System.Runtime.CompilerServices;
 using Datadog.Trace.Ci.Stubs;
 using Datadog.Trace.SourceGenerators;
 
@@ -44,6 +45,7 @@ public static ITestModule Create(string name, string framework, string framework
         => InternalCreate(name, framework, frameworkVersion, startDate);
 
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     internal static ITestModule InternalCreate(string name, string? framework, string? frameworkVersion, DateTimeOffset? startDate)
         => NullTestModule.Instance;
 }

tracer/src/Datadog.Trace.Manual/Ci/TestSession.cs

@@ -4,6 +4,7 @@
 // </copyright>
 #nullable enable
 
+using System.Runtime.CompilerServices;
 using Datadog.Trace.Ci.Stubs;
 using Datadog.Trace.SourceGenerators;
 
@@ -65,6 +66,7 @@ public static ITestSession GetOrCreate(string command, string? workingDirectory,
         => InternalGetOrCreate(command, workingDirectory, framework, startDate, propagateEnvironmentVariables);
 
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     internal static ITestSession InternalGetOrCreate(string command, string? workingDirectory, string? framework, DateTimeOffset? startDate, bool propagateEnvironmentVariables = false)
         => NullTestSession.Instance;
 }

tracer/src/Datadog.Trace.Manual/Configuration/GlobalSettings.cs

@@ -3,6 +3,7 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
 // </copyright>
 
+using System.Runtime.CompilerServices;
 using Datadog.Trace.SourceGenerators;
 
 namespace Datadog.Trace.Configuration;
@@ -22,6 +23,7 @@ internal GlobalSettings()
     /// </summary>
     /// <param name="enabled">Whether debug is enabled.</param>
     [Instrumented]
+    [MethodImpl(MethodImplOptions.NoInlining)]
     public static void SetDebugEnabled(bool enabled)
     {
     }

tracer/src/Datadog.Trace.Manual/Configuration/ImmutableIntegrationSettings.cs

@@ -5,6 +5,7 @@
 
 #nullable enable
 
+using System.Runtime.CompilerServices;
 using Datadog.Trace.SourceGenerators;
 
 namespace Datadog.Trace.Configuration;
@@ -30,27 +31,43 @@ internal ImmutableIntegrationSettings(string name)
     /// <summary>
     /// Gets the name of the integration. Used to retrieve integration-specific settings.
     /// </summary>
-    [Instrumented]
-    public string IntegrationName { get; }
+    public string IntegrationName
+    {
+        [Instrumented]
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        get;
+    }
 
     /// <summary>
     /// Gets a value indicating whether
     /// this integration is enabled.
     /// </summary>
-    [Instrumented]
-    public bool? Enabled { get; }
+    public bool? Enabled
+    {
+        [Instrumented]
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        get;
+    }
 
     /// <summary>
     /// Gets a value indicating whether
     /// Analytics are enabled for this integration.
     /// </summary>
-    [Instrumented]
-    public bool? AnalyticsEnabled { get; }
+    public bool? AnalyticsEnabled
+    {
+        [Instrumented]
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        get;
+    }
 
     /// <summary>
     /// Gets a value between 0 and 1 (inclusive)
     /// that determines the sampling rate for this integration.
     /// </summary>
-    [Instrumented]
-    public double AnalyticsSampleRate { get; }
+    public double AnalyticsSampleRate
+    {
+        [Instrumented]
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        get;
+    }
 }

tracer/src/Datadog.Trace.Manual/Configuration/ImmutableIntegrationSettingsCollection.cs

@@ -5,6 +5,7 @@
 
 #nullable enable
 
+using System.Runtime.CompilerServices;
 using Datadog.Trace.SourceGenerators;
 
 namespace Datadog.Trace.Configuration;
@@ -26,9 +27,10 @@ internal ImmutableIntegrationSettingsCollection(Dictionary<string, ImmutableInte
     /// </summary>
     /// <param name="integrationName">The name of the integration.</param>
     /// <returns>The integration-specific settings for the specified integration.</returns>
-    [Instrumented]
     public ImmutableIntegrationSettings this[string integrationName]
     {
+        [Instrumented]
+        [MethodImpl(MethodImplOptions.NoInlining)]
         get
         {
             if (Settings.TryGetValue(integrationName, out var setting))