Introduce TelemetryListener

src/Polly.Core/CircuitBreaker/OnCircuitClosedArguments.cs

@@ -5,6 +5,9 @@ namespace Polly.CircuitBreaker;
 /// <summary>
 /// Arguments used by <see cref="CircuitBreakerStrategyOptions{TResult}.OnClosed"/> event.
 /// </summary>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct OnCircuitClosedArguments
 {
     /// <summary>

src/Polly.Core/CircuitBreaker/OnCircuitHalfOpenedArguments.cs

@@ -5,6 +5,9 @@ namespace Polly.CircuitBreaker;
 /// <summary>
 /// Arguments used by <see cref="CircuitBreakerStrategyOptions{TResult}.OnHalfOpened"/> event.
 /// </summary>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct OnCircuitHalfOpenedArguments
 {
     /// <summary>

src/Polly.Core/CircuitBreaker/OnCircuitOpenedArguments.cs

@@ -5,6 +5,9 @@ namespace Polly.CircuitBreaker;
 /// <summary>
 /// Arguments used by <see cref="CircuitBreakerStrategyOptions{TResult}.OnOpened"/> event.
 /// </summary>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct OnCircuitOpenedArguments
 {
     /// <summary>

src/Polly.Core/Fallback/OnFallbackArguments.cs

@@ -3,6 +3,9 @@ namespace Polly.Fallback;
 /// <summary>
 /// Represents arguments used in fallback handling scenarios.
 /// </summary>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct OnFallbackArguments
 {
 }

src/Polly.Core/Hedging/OnHedgingArguments.cs

@@ -5,6 +5,9 @@ namespace Polly.Hedging;
 /// <summary>
 /// Represents arguments used by the on-hedging event.
 /// </summary>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct OnHedgingArguments
 {
     /// <summary>

src/Polly.Core/Retry/OnRetryArguments.cs

@@ -5,6 +5,9 @@ namespace Polly.Retry;
 /// <summary>
 /// Represents the arguments used by <see cref="RetryStrategyOptions{TResult}.OnRetry"/> for handling the retry event.
 /// </summary>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct OnRetryArguments
 {
     /// <summary>

src/Polly.Core/Telemetry/ExecutionAttemptArguments.cs

@@ -5,6 +5,9 @@
 /// <summary>
 /// Arguments that encapsulate the execution attempt for retries or hedging.
 /// </summary>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct ExecutionAttemptArguments
 {
     /// <summary>

src/Polly.Core/Telemetry/PipelineExecutedArguments.cs

@@ -5,6 +5,9 @@
 /// <summary>
 /// Arguments that indicate the pipeline execution started.
 /// </summary>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct PipelineExecutedArguments
 {
     /// <summary>

src/Polly.Core/Telemetry/PipelineExecutingArguments.cs

@@ -3,6 +3,9 @@
 /// <summary>
 /// Arguments that indicate the pipeline execution started.
 /// </summary>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct PipelineExecutingArguments
 {
 }

src/Polly.Core/Telemetry/TelemetryEventArguments.cs

@@ -7,6 +7,9 @@
 /// </summary>
 /// <typeparam name="TResult">The type of result.</typeparam>
 /// <typeparam name="TArgs">The arguments associated with the resilience event.</typeparam>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct TelemetryEventArguments<TResult, TArgs>
 {
     /// <summary>

src/Polly.Core/Timeout/OnTimeoutArguments.cs

@@ -5,6 +5,9 @@ namespace Polly.Timeout;
 /// <summary>
 /// Arguments used by the timeout strategy to notify that a timeout occurred.
 /// </summary>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct OnTimeoutArguments
 {
     /// <summary>

src/Polly.Core/Timeout/TimeoutGeneratorArguments.cs

@@ -5,6 +5,9 @@ namespace Polly.Timeout;
 /// <summary>
 /// Arguments used by the timeout strategy to retrieve a timeout for current execution.
 /// </summary>
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
 public readonly struct TimeoutGeneratorArguments
 {
     /// <summary>

src/Polly.Extensions/Telemetry/EnrichmentContext.cs

@@ -9,6 +9,7 @@
 /// <typeparam name="TArgs">The type of the arguments attached to the resilience event.</typeparam>
 /// <remarks>
 /// This context is passed to enrichers in <see cref="TelemetryOptions.MeteringEnrichers"/>.
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
 /// </remarks>
 public readonly struct EnrichmentContext<TResult, TArgs>
 {

src/Polly.RateLimiting/OnRateLimiterRejectedArguments.cs

@@ -2,13 +2,18 @@
 
 namespace Polly.RateLimiting;
 
+#pragma warning disable CA1815 // Override equals and operator equals on value types
+
 /// <summary>
 /// The arguments used by the <see cref="RateLimiterStrategyOptions.OnRejected"/>.
 /// </summary>
-public sealed class OnRateLimiterRejectedArguments
+/// <remarks>
+/// Always use constructor when creating this struct, otherwise we do not guarantee the binary compatibility.
+/// </remarks>
+public readonly struct OnRateLimiterRejectedArguments
 {
     /// <summary>
-    /// Initializes a new instance of the <see cref="OnRateLimiterRejectedArguments"/> class.
+    /// Initializes a new instance of the <see cref="OnRateLimiterRejectedArguments"/> struct.
     /// </summary>
     /// <param name="context">The context associated with the execution of a user-provided callback.</param>
     /// <param name="lease">The lease that has no permits and was rejected by the rate limiter.</param>

src/Polly.RateLimiting/PublicAPI.Unshipped.txt

@@ -3,6 +3,7 @@ Polly.RateLimiterResiliencePipelineBuilderExtensions
 Polly.RateLimiting.OnRateLimiterRejectedArguments
 Polly.RateLimiting.OnRateLimiterRejectedArguments.Context.get -> Polly.ResilienceContext!
 Polly.RateLimiting.OnRateLimiterRejectedArguments.Lease.get -> System.Threading.RateLimiting.RateLimitLease!
+Polly.RateLimiting.OnRateLimiterRejectedArguments.OnRateLimiterRejectedArguments() -> void
 Polly.RateLimiting.OnRateLimiterRejectedArguments.OnRateLimiterRejectedArguments(Polly.ResilienceContext! context, System.Threading.RateLimiting.RateLimitLease! lease, System.TimeSpan? retryAfter) -> void
 Polly.RateLimiting.OnRateLimiterRejectedArguments.RetryAfter.get -> System.TimeSpan?
 Polly.RateLimiting.RateLimiterRejectedException
@@ -16,7 +17,7 @@ Polly.RateLimiting.RateLimiterRejectedException.RetryAfter.get -> System.TimeSpa
 Polly.RateLimiting.RateLimiterStrategyOptions
 Polly.RateLimiting.RateLimiterStrategyOptions.DefaultRateLimiterOptions.get -> System.Threading.RateLimiting.ConcurrencyLimiterOptions!
 Polly.RateLimiting.RateLimiterStrategyOptions.DefaultRateLimiterOptions.set -> void
-Polly.RateLimiting.RateLimiterStrategyOptions.OnRejected.get -> System.Func<Polly.RateLimiting.OnRateLimiterRejectedArguments!, System.Threading.Tasks.ValueTask>?
+Polly.RateLimiting.RateLimiterStrategyOptions.OnRejected.get -> System.Func<Polly.RateLimiting.OnRateLimiterRejectedArguments, System.Threading.Tasks.ValueTask>?
 Polly.RateLimiting.RateLimiterStrategyOptions.OnRejected.set -> void
 Polly.RateLimiting.RateLimiterStrategyOptions.RateLimiter.get -> Polly.RateLimiting.ResilienceRateLimiter?
 Polly.RateLimiting.RateLimiterStrategyOptions.RateLimiter.set -> void