Add clientName and commandName to HandlerExecutionContext (#931)

Author: Steven Yuan

.changeset/calm-cows-fix.md

@@ -0,0 +1,5 @@
+---
+"@smithy/types": patch
+---
+
+Add `clientName` and `commandName` to `HandlerExecutionContext`

packages/types/src/middleware.ts

@@ -499,6 +499,16 @@ export interface HandlerExecutionContext {
    */
   logger?: Logger;
 
+  /**
+   * Name of the service the operation is being sent to.
+   */
+  clientName?: string;
+
+  /**
+   * Name of the operation being executed.
+   */
+  commandName?: string;
+
   /**
    * Additional user agent that inferred by middleware. It can be used to save
    * the internal user agent sections without overriding the `customUserAgent`