# io

Transport-agnostic I/O primitives shared by the networking modules.

Header-only (`tw::io`), namespace `tw::net`.

| Path | Contents |
| --- | --- |
| `io/Read.hpp`, `io/Write.hpp` | `Read<T>` / `Write<T>` interfaces every stream implements (`read_into`, `write`, `flush`, plus `read_exact` helpers) |
| `io/BufferReader.hpp`, `io/BufferWriter.hpp` | Buffering decorators that wrap another `Read<T>` / `Write<T>` |
| `bytebuffer/ByteBuffer.hpp` | `RingByteBuffer` — circular buffer over a caller-owned `std::span` |
| `bytebuffer/ByteBufferReader.hpp`, `ByteBufferWriter.hpp` | Linear cursor read/write over a `std::span` |
| `bytebuffer/ByteBufferCodec.hpp`, `ByteBufferEncoder.hpp`, `ByteBufferDecoder.hpp` | Typed push/pop on top of `RingByteBuffer`, specialize `ByteBufferCodec<T>` for custom types |
| `NetworkError.hpp` | errno-backed error type returned by `Read` / `Write` |

This module owns no sockets and links no transport — it sits below `tw::network`
and `tw::quicr` so both can share buffers and stream interfaces without depending
on each other.