[Docs] Unify strategy descriptions and add Telemetry sections

docs/strategies/retry.md

@@ -111,6 +111,65 @@ new ResiliencePipelineBuilder<HttpResponseMessage>().AddRetry(optionsExtractDela
 | `DelayGenerator`   | `null`                                                  | This optional delegate allows you to **dynamically** calculate the retry delay by utilizing information that is only available at runtime (like the attempt number). |
 | `OnRetry`          | `null`                                                  | If provided then it will be invoked before the strategy delays the next attempt.                                                                                     |
 
+## Telemetry
+
+The retry strategy reports the following telemetry events:
+
+| Event Name          | Event Severity            | When?                                                 |
+|---------------------|---------------------------|-------------------------------------------------------|
+| `Execution Attempt` | `Information` / `Warning` | Just before the strategy calculates the next delay    |
+| `OnRetry`           | `Warning`                 | Just before the strategy calls the `OnRetry` delegate |
+
+Here are some sample events:
+
+### Unhandled case
+
+If the retry strategy does not perform any retries then the reported telemetry events' severity will be `Information`:
+
+```none
+Execution attempt. Source: 'MyApplication/MyTestPipeline/MyRetryStrategy', Operation Key: 'MyRetryableOperation', Result: '1', Handled: 'False', Attempt: '0', Execution Time: '110.952'
+
+Execution attempt. Source: 'MyApplication/MyTestPipeline/MyRetryStrategy', Operation Key: 'MyRetryableOperation', Result: 'Failed', Handled: 'False', Attempt: '0', Execution Time: '5.2194'
+    System.Exception: Failed
+        at Program.<>c.<Main>b__0_1(ResilienceContext ctx)
+        ...
+        at Polly.ResiliencePipeline.<>c.<<ExecuteAsync>b__1_0>d.MoveNext() in /_/src/Polly.Core/ResiliencePipeline.Async.cs:line 67
+```
+
+### Handled case
+
+If the retry strategy performs some retries then the reported telemetry events' severity will be `Warning`:
+
+```none
+Execution attempt. Source: 'MyApplication/MyTestPipeline/MyRetryStrategy', Operation Key: 'MyRetryableOperation', Result: 'Failed', Handled: 'True', Attempt: '0', Execution Time: '5.0397'
+      System.Exception: Failed
+         at Program.<>c.<Main>b__0_1(ResilienceContext ctx)
+         ...
+         at Polly.ResiliencePipeline.<>c.<<ExecuteAsync>b__1_0>d.MoveNext() in /_/src/Polly.Core/ResiliencePipeline.Async.cs:line 67
+
+Resilience event occurred. EventName: 'OnRetry', Source: 'MyApplication/MyTestPipeline/MyRetryStrategy', Operation Key: 'MyRetryableOperation', Result: 'Failed'
+    System.Exception: Failed
+        at Program.<>c.<Main>b__0_1(ResilienceContext ctx)
+        ...
+        at Polly.ResiliencePipeline.<>c.<<ExecuteAsync>b__1_0>d.MoveNext() in /_/src/Polly.Core/ResiliencePipeline.Async.cs:line 67
+
+
+Execution attempt. Source: 'MyApplication/MyTestPipeline/MyRetryStrategy', Operation Key: 'MyRetryableOperation', Result: 'Failed', Handled: 'True', Attempt: '1', Execution Time: '0.1159'
+      System.Exception: Failed
+         at Program.<>c.<Main>b__0_1(ResilienceContext ctx)
+         ...
+         at Polly.ResiliencePipeline.<>c.<<ExecuteAsync>b__1_0>d.MoveNext() in /_/src/Polly.Core/ResiliencePipeline.Async.cs:line 67
+```
+
+> [!NOTE]
+> Please note that the `OnRetry` telemetry event will be reported **only if** the retry strategy performs any retry attempts.
+>
+> On the other hand the `Execution attempt` event will be **always** reported regardless whether the strategy has to perform any retries.
+>
+> Also remember that the `Attempt: '0'` means the original attempt.
+
+For further information please check out the [telemetry page](../advanced/telemetry.html).
+
 ## Calculation of the next delay
 
 If the `ShouldHandle` predicate returns `true` and the next attempt number is not greater than `MaxRetryAttempts` then the retry strategy calculates the next delay.

docs/strategies/timeout.md

@@ -149,7 +149,7 @@ Resilience event occurred. EventName: 'OnTimeout', Source: 'MyApplication/MyTest
 > [!NOTE]
 > Please note that the `OnTimeout` telemetry event will be reported **only if** the timeout strategy cancels the provided callback execution.
 >
-> So, if the callback either finishes on time or throws an exception then there will be no telemetry log.
+> So, if the callback either finishes on time or throws an exception then there will be no telemetry emitted.
 >
 > Also remember that the `Result` will be **always** empty for the `OnTimeout` telemetry event.