uuid - Workflow.uuid meta - Any additional information to pass to the backend which is not workflow properties callback - f(err, workflow)
function getWorkflow(uuid, meta, callback) {
            if (typeof (meta) === 'function') {
                callback = meta;
                meta = {};
            }

            if (workflows[uuid]) {
                return callback(null, clone(workflows[uuid]));
            } else {
                return callback(new e.BackendResourceNotFoundError(sprintf(
                  'Workflow with uuid \'%s\' does not exist', uuid)));
            }
        }