### Describe the bug The C# generator emits an explicit conversion operator from `ClientResult` for every streaming event class, for example: ```csharp public static explicit operator InternalImageEditPartialImageEvent(ClientResult result) { PipelineResponse response = result.GetRawResponse(); using JsonDocument document = JsonDocument.Parse(response.Content, ModelSerializationExtensions.JsonDocumentOptions); return DeserializeInternalImageEditPartialImageEditPartialImageEvent(document.RootElement, ModelSerializationExtensions.WireOptions); } ``` This conversion is useful for ordinary protocol methods that return a `ClientResult` whose raw response can be deserialized into a model. However, individual streaming events are not returned as plain `ClientResult` values: streaming protocol methods return `Task<AsyncStreamingClientResult<SseItem<BinaryData>>>` instead. Consequently, there is no practical call site for casting a `ClientResult` to a streaming-event type, and these generated operators are unused API surface. Update the C# generator so it does not generate `ClientResult` explicit conversion operators for streaming event classes, while preserving the operator for models returned by ordinary protocol methods where it is applicable. ### Reproduction Generate a C# client for a service that has streaming operations/events, then inspect a generated streaming event class such as `InternalImageEditPartialImageEvent`. Expected: streaming event classes do not contain an explicit conversion operator from `ClientResult`. Actual: each streaming event class contains `public static explicit operator <StreamingEvent>(ClientResult result)`, even though no streaming protocol operation returns an individual event wrapped in a plain `ClientResult`. ### Checklist - [x] Follow our [Code of Conduct](https://github.com/microsoft/typespec/blob/main/CODE_OF_CONDUCT.md) - [x] Check that there isn't already an issue that request the same bug to avoid creating a duplicate. - [x] Check that this is a concrete bug. For Q&A open a [GitHub Discussion](https://github.com/Microsoft/typespec/discussions). - [x] The provided reproduction is a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example) of the bug.