(mongodb >=2.1.0)
MongoDB\Driver\BulkWriteCommandResult::getInsertResults — Returns verbose results for successful inserts
   Since _id fields for inserted documents are generated by
   the extension, the value of insertedId in each result
   will match the return value of
   MongoDB\Driver\BulkWriteCommand::insertOne() for
   the corresponding insert operation.
  
This function has no parameters.
   Returns a document containing the result of each successful insert
   operation, or null if verbose results were not requested. The document
   keys will correspond to the index of the write operation from
   MongoDB\Driver\BulkWriteCommand.
  
Example #1 MongoDB\Driver\BulkWriteCommandResult::getInsertResults() example
<?php
$manager = new MongoDB\Driver\Manager;
$bulk = new MongoDB\Driver\BulkWriteCommand(['verboseResults' => true]);
$generatedId = $bulk->insertOne('db.coll', ['x' => 1]);
$bulk->updateOne('db.coll', ['x' => 1], ['$set' => ['y' => 3]]);
$bulk->updateOne('db.coll', ['x' => 2], ['$set' => ['y' => 1]], ['upsert' => true]);
$bulk->updateOne('db.coll', ['x' => 3], ['$set' => ['y' => 2]], ['upsert' => true]);
$bulk->deleteMany('db.coll', []);
$result = $manager->executeBulkWriteCommand($bulk);
var_dump($generatedId);
var_dump($result->getInsertResults()->toPHP());
?>The above example will output something similar to:
object(MongoDB\BSON\ObjectId)#3 (1) {
  ["oid"]=>
  string(24) "67f7ee69783dcce702097b41"
}
object(stdClass)#8 (1) {
  ["0"]=>
  object(stdClass)#7 (1) {
    ["insertedId"]=>
    object(MongoDB\BSON\ObjectId)#6 (1) {
      ["oid"]=>
      string(24) "67f7ee69783dcce702097b41"
    }
  }
}
