add flush to global usage api

Author: nicktrn

packages/core/src/v3/usage/api.ts

@@ -44,6 +44,10 @@ export class UsageAPI implements UsageManager {
     return this.#getUsageManager().sample();
   }
 
+  public flush(): Promise<void> {
+    return this.#getUsageManager().flush();
+  }
+
   #getUsageManager(): UsageManager {
     return getGlobal(API_NAME) ?? NOOP_USAGE_MANAGER;
   }

packages/core/src/v3/usage/devUsageManager.ts

@@ -48,6 +48,8 @@ export class DevUsageManager implements UsageManager {
 
   disable(): void {}
 
+  async flush(): Promise<void> {}
+
   sample(): UsageSample | undefined {
     return this._firstMeasurement?.sample();
   }

packages/core/src/v3/usage/noopUsageManager.ts

@@ -5,6 +5,10 @@ export class NoopUsageManager implements UsageManager {
     // Noop
   }
 
+  async flush(): Promise<void> {
+    // Noop
+  }
+
   start(): UsageMeasurement {
     return {
       sample: () => ({ cpuTime: 0, wallTime: 0 }),

packages/core/src/v3/usage/types.ts

@@ -13,4 +13,5 @@ export interface UsageManager {
   stop(measurement: UsageMeasurement): UsageSample;
   sample(): UsageSample | undefined;
   pauseAsync<T>(cb: () => Promise<T>): Promise<T>;
+  flush(): Promise<void>;
 }