Actions `cluster:admin/repository/analyze/blob` and `cluster:admin/repository/analyze/register` and so on are only invoked via the transport service, they do not need to register as client actions so we can drop the `ActionType` instance. Instead the root `RepositoryAnalyzeAction` should create and register all these transport actions itself. But even the root `RepositoryAnalyzeAction` should not be an `ActionType` derivative, we should just declare an `ActionType` instance directly. Moreover we can use `ActionType#localOnly` since the client action does not run on remote clusters.
x-pack/plugin/snapshot-repo-test-kit/src/main/java/org/elasticsearch/repositories/blobstore/testkit/GetBlobChecksumAction.java
out.writeVLong(rangeStart);
            out.writeVLong(rangeEnd);
        }
        @Override
        public String getDescription() {
            return "retrieve ["
                + (isWholeBlob() ? "whole blob" : (getRangeStart() + "-" + getRangeEnd()))
                + "] from ["
                + getRepositoryName()
                + ":"
                + getBlobPath()
                + "/"
                + getBlobName()
                + "]";
        }
        @Override
        public String toString() {
            return "GetRepositoryBlobChecksumRequest{" + getDescription() + "}";
        }
        @Override
        public Task createTask(long id, String type, String action, TaskId parentTaskId, Map<String, String> headers) {
            return new CancellableTask(id, type, action, getDescription(), parentTaskId, headers) {
                @Override
                public boolean shouldCancelChildrenOnCancellation() {
                    return false; 
                }
            };
        }
    }
    public static class Response extends ActionResponse {