Revert "[BREAK IN 2.20.0] Remove support for Batch Grouping configura…

…tion" (#23563)

We have partners that still depend on this flag, so putting it back.

reverts #23336

packages/runtime/container-runtime/api-report/container-runtime.legacy.alpha.api.md

@@ -193,6 +193,8 @@ export interface IContainerRuntimeMetadata extends ICreateContainerMetadata, IGC
 export interface IContainerRuntimeOptions {
     readonly chunkSizeInBytes?: number;
     readonly compressionOptions?: ICompressionRuntimeOptions;
+    // @deprecated
+    readonly enableGroupedBatching?: boolean;
     readonly enableRuntimeIdCompressor?: IdCompressorMode;
     readonly explicitSchemaControl?: boolean;
     // (undocumented)

packages/runtime/container-runtime/src/containerRuntime.ts

@@ -507,6 +507,16 @@ export interface IContainerRuntimeOptions {
 	 */
 	readonly enableRuntimeIdCompressor?: IdCompressorMode;
 
+	/**
+	 * If enabled, the runtime will group messages within a batch into a single
+	 * message to be sent to the service.
+	 * The grouping and ungrouping of such messages is handled by the "OpGroupingManager".
+	 *
+	 * By default, the feature is enabled. This feature can only be disabled when compression is also disabled.
+	 * @deprecated  The ability to disable Grouped Batching is deprecated and will be removed in a future release. This feature is required for the proper functioning of the Fluid Framework.
+	 */
+	readonly enableGroupedBatching?: boolean;
+
 	/**
 	 * When this property is set to true, it requires runtime to control is document schema properly through ops
 	 * The benefit of this mode is that clients who do not understand schema will fail in predictable way, with predictable message,
@@ -1549,7 +1559,6 @@ export class ContainerRuntime
 		// Backfill in defaults for the internal runtimeOptions, since they may not be present on the provided runtimeOptions object
 		this.runtimeOptions = {
 			flushMode: defaultFlushMode,
-			enableGroupedBatching: true,
 			...runtimeOptions,
 		};
 		this.logger = createChildLogger({ logger: this.baseLogger });