fix(host-metrics): fallback to process.memoryUsage() (open-telemetry#…

…1471)

Co-authored-by: Marc Pichler <marc.pichler@dynatrace.com>
Co-authored-by: Daniel Dyla <dyladan@users.noreply.github.com>

packages/opentelemetry-host-metrics/src/stats/common.ts

@@ -109,5 +109,10 @@ export function getMemoryData(): MemoryData {
  * including all C++ and JavaScript objects and code.
  */
 export function getProcessMemoryData(): number {
-  return process.memoryUsage.rss();
+  // `process.memoryUsage.rss` is a faster alternative introduced in v14.18.0.
+  // Prefer it if available.
+  if (process.memoryUsage.rss) {
+    return process.memoryUsage.rss();
+  }
+  return process.memoryUsage().rss;
 }