// SPDX-License-Identifier: Apache-2.0
// Copyright (c) 2025 ReifyDB
//! Flow definition surface. SDK consumers describe a streaming computation here as a graph of operators,
//! connectors, and inputs; the resulting structure is what the engine compiles into the dataflow that `sub-flow`
//! runs. The builder hides the catalog plumbing so an extension author does not have to know how flows are
//! persisted.