feat: add method for sending metrics

src/index.ts

@@ -71,4 +71,34 @@ export class Logger {
       method: "POST",
     });
   }
+
+  /**
+   * Sends a counter metric to the alerting service.
+   * The alerting service is configured to handle aggregation, so you can send
+   * summative counts or individual increments. (e.g. Send a count of all users, or send a count of 1 every time a user joins).
+   * @param name -- The name of the metric to track.
+   * @param value -- The value of the metric to insert.
+   * @param metadata -- Any metadata to attach to the metric.
+   */
+  public async metric(
+    name: string,
+    value: number,
+    metadata: Record<string, string | number | boolean>,
+  ): Promise<void> {
+    await fetch(`${this.url}/metric`, {
+      body: JSON.stringify({
+        application: this.application,
+        metadata:    metadata,
+        name:        name,
+        value:       value,
+      }),
+      headers: {
+        // eslint-disable-next-line @typescript-eslint/naming-convention -- Standard header name.
+        "Authorization": this.token,
+        // eslint-disable-next-line @typescript-eslint/naming-convention -- Standard header name.
+        "Content-Type":  "application/json",
+      },
+      method: "POST",
+    });
+  }
 }