DRIVERS-2968 Relax index type requirements in bulk write spec (#1661)

Author: isabelatkinson

source/crud/bulk-write.md

@@ -353,17 +353,17 @@ class BulkWriteResult {
     /**
      * The results of each individual insert operation that was successfully performed.
      */
-    insertResults: Map<Int64, InsertOneResult>;
+    insertResults: Map<Index, InsertOneResult>;
 
     /**
      * The results of each individual update operation that was successfully performed.
      */
-    updateResults: Map<Int64, UpdateResult>;
+    updateResults: Map<Index, UpdateResult>;
 
     /**
      * The results of each individual delete operation that was successfully performed.
      */
-    deleteResults: Map<Int64, DeleteResult>;
+    deleteResults: Map<Index, DeleteResult>;
 }
 
 class InsertOneResult {
@@ -451,7 +451,7 @@ class BulkWriteException {
      * Errors that occurred during the execution of individual write operations. This map will
      * contain at most one entry if the bulk write was ordered.
      */
-    writeErrors: Map<Int64, WriteError>;
+    writeErrors: Map<Index, WriteError>;
 
     /**
      * The results of any successful operations that were performed before the error was
@@ -461,6 +461,13 @@ class BulkWriteException {
 }
 ```
 
+### Index Types
+
+The `insertResults`, `updateResults`, and `deleteResults` maps in `BulkWriteResult` and the `writeErrors` map in
+`BulkWriteException` specify `Index` as their key type. This value corresponds to the index of the operation in the
+`writeModels` list that was provided to `MongoClient.bulkWrite`. Drivers SHOULD use their language's standard numeric
+type for indexes for this type (e.g. `usize` in Rust). If no standard index type exists, drivers MUST use `Int64`.
+
 ## Building a `bulkWrite` Command
 
 The `bulkWrite` server command has the following format:
@@ -852,6 +859,8 @@ batch-splitting to standardize implementations across drivers and simplify batch
 
 ## **Changelog**
 
+- 2024-09-18: Relax numeric type requirements for indexes.
+
 - 2024-05-17: Update specification status to "Accepted".
 
 - 2024-05-10: Improve rendered format for JSON-like code blocks.