[metrics] Document view level cardinality limit (#5321)

Co-authored-by: Cijo Thomas <[email protected]>

Author: reyang

docs/metrics/README.md

@@ -356,18 +356,13 @@ predictable and reliable behavior when excessive cardinality happens, whether it
 was due to a malicious attack or developer making mistakes while writing code.
 
 OpenTelemetry has a default cardinality limit of `2000` per metric. This limit
-can be configured at `MeterProvider` level using
+can be configured at `MeterProvider` level using the
 `SetMaxMetricPointsPerMetricStream` method, or at individual
 [view](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk.md#view)
-level. Refer to this
+level using `MetricStreamConfiguration.CardinalityLimit`. Refer to this
 [doc](../../docs/metrics/customizing-the-sdk/README.md#changing-maximum-metricpoints-per-metricstream)
 for more information.
 
-> [!NOTE]
-> Setting cardinality limit per view is not yet implemented in OpenTelemetry
-  .NET. You can track the progress by following this
-  [issue](https://github.com/open-telemetry/opentelemetry-dotnet/issues/5296).
-
 Given a metric, once the cardinality limit is reached, any new measurement which
 cannot be independently aggregated because of the limit will be aggregated using
 the [overflow

docs/metrics/customizing-the-sdk/README.md

@@ -444,10 +444,16 @@ AnotherFruitCounter.Add(5, new("name", "banana"), new("color", "yellow")); // Ex
 AnotherFruitCounter.Add(4, new("name", "mango"), new("color", "yellow")); // Not exported
 ```
 
-> [!NOTE]
-> The above limit is *per* metric stream, and applies to all the metric
-streams. There is no ability to apply different limits for each instrument at
-this moment.
+To set the [cardinality limit](../README.md#cardinality-limits) at individual
+metric level, use `MetricStreamConfiguration.CardinalityLimit`:
+
+```csharp
+var meterProvider = Sdk.CreateMeterProviderBuilder()
+    .AddMeter("MyCompany.MyProduct.MyLibrary")
+    .AddView(instrumentName: "MyFruitCounter", new MetricStreamConfiguration { CardinalityLimit = 10 })
+    .AddConsoleExporter()
+    .Build();
+```
 
 ### Exemplars
 

docs/metrics/getting-started-console/Program.cs

@@ -17,6 +17,9 @@ public static void Main()
             .AddConsoleExporter()
             .Build();
 
+        // In this example, we have low cardinality which is below the 2000
+        // default limit. If you have high cardinality, you need to set the
+        // cardinality limit properly.
         MyFruitCounter.Add(1, new("name", "apple"), new("color", "red"));
         MyFruitCounter.Add(2, new("name", "lemon"), new("color", "yellow"));
         MyFruitCounter.Add(1, new("name", "lemon"), new("color", "yellow"));

docs/metrics/getting-started-console/README.md

@@ -69,10 +69,10 @@ MyFruitCounter.Add(2, new("name", "lemon"), new("color", "yellow"));
 MyFruitCounter.Add(1, new("name", "lemon"), new("color", "yellow"));
 ```
 
-An OpenTelemetry
-[MeterProvider](#meterprovider)
-is configured to subscribe to instruments from the Meter
-`MyCompany.MyProduct.MyLibrary`, and aggregate the measurements in-memory. The
+An OpenTelemetry [MeterProvider](#meterprovider) is configured to subscribe to
+an instrument named "MyFruitCounter" from the Meter
+`MyCompany.MyProduct.MyLibrary`, and aggregate the measurements in-memory with a
+default [cardinality limit](../README.md#cardinality-limits) of `2000`. The
 pre-aggregated metrics are exported to a `ConsoleExporter`.
 
 ```csharp
@@ -82,6 +82,20 @@ var meterProvider = Sdk.CreateMeterProviderBuilder()
     .Build();
 ```
 
+> [!NOTE]
+> If you need to collect metrics with cardinality higher than the default limit
+  `2000`, please follow the [cardinality
+  limits](../README.md#cardinality-limits) guidance. Here is a quick example of
+  how to change the cardinality limit to `10` for this particular metric:
+
+  ```csharp
+  var meterProvider = Sdk.CreateMeterProviderBuilder()
+      .AddMeter("MyCompany.MyProduct.MyLibrary")
+      .AddView(instrumentName: "MyFruitCounter", new MetricStreamConfiguration { CardinalityLimit = 10 })
+      .AddConsoleExporter()
+      .Build();
+  ```
+
 ```mermaid
 graph LR