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//! The internal implementation details of OpenDAL.
//!
//! OpenDAL provides unified abstraction via two-level API sets:
//!
//! - Public API like [`Operator`] provides user-level API.
//! - Raw API like [`Service`], [`Layer`] provides developer-level API.
//!
//! OpenDAL tries its best to keep the public API stable. But raw APIs
//! may change between minor releases from time to time. So most users
//! should only use the public API. Developers use raw APIs to implement
//! storage services or their own [`Layer`].
//!
//! In this section, we will talk about the following components:
//!
//! - [`Service`][accessor]: to connect underlying storage services.
//! - [`Layer`][layer]: middleware/interceptor between storage services.
//!
//! The relation between [`Service`], [`Layer`], [`Servicer`], [`OperationContext`],
//! and [`Operator`] looks like the following:
//!
//! ```text
//! ┌──────────────┐     ┌──────────────────────────────┐     ┌──────────────┐
//! │ Service      │     │ Servicer                     │     │ Operator     │
//! │ builders     ├────►│ + Layer::apply_* replay      ├────►│ srv + ctx    │
//! └──────────────┘     │ + OperationContext resources │     └──────────────┘
//!                      └──────────────────────────────┘
//! ```
//!
//! [`Builder`]: crate::Builder
//! [`Operator`]: crate::Operator
//! [`Service`]: crate::raw::Service
//! [`Servicer`]: crate::raw::Servicer
//! [`OperationContext`]: crate::raw::OperationContext
//! [`Layer`]: crate::raw::Layer

pub mod accessor;
pub mod layer;
