fix: read concern only supported for mapReduce without inline

Author: mbroadst

lib/core/sessions.js

@@ -625,17 +625,24 @@ class ServerSessionPool {
 
 // TODO: this should be codified in command construction
 // @see https://github.com/mongodb/specifications/blob/master/source/read-write-concern/read-write-concern.rst#read-concern
-function commandSupportsReadConcern(command) {
-  return (
+function commandSupportsReadConcern(command, options) {
+  if (
     command.aggregate ||
     command.count ||
     command.distinct ||
     command.find ||
-    command.mapReduce ||
     command.parallelCollectionScan ||
     command.geoNear ||
     command.geoSearch
-  );
+  ) {
+    return true;
+  }
+
+  if (command.mapReduce && options.out && (options.out.inline === 1 || options.out === 'inline')) {
+    return true;
+  }
+
+  return false;
 }
 
 /**