@Override
    public CompletableFuture<OffsetDeleteResponseData> deleteOffsets(
        RequestContext context,
        OffsetDeleteRequestData request,
        BufferSupplier bufferSupplier
    ) {
        if (!isActive.get()) {
            return CompletableFuture.completedFuture(new OffsetDeleteResponseData()
                .setErrorCode(Errors.COORDINATOR_NOT_AVAILABLE.code())
            );
        }

        if (!isGroupIdNotEmpty(request.groupId())) {
            return CompletableFuture.completedFuture(new OffsetDeleteResponseData()
                .setErrorCode(Errors.INVALID_GROUP_ID.code())
            );
        }

        return runtime.scheduleWriteOperation(
            "delete-offsets",
            topicPartitionFor(request.groupId()),
            Duration.ofMillis(config.offsetCommitTimeoutMs()),
            coordinator -> coordinator.deleteOffsets(context, request)
        ).exceptionally(exception -> handleOperationException(
            "delete-offsets",
            request,
            exception,
            (error, __) -> new OffsetDeleteResponseData().setErrorCode(error.code())
        ));
    }
See {@link GroupCoordinator#deleteOffsets(RequestContext, OffsetDeleteRequestData, BufferSupplier)}.
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupCoordinatorService.java