IronFix Core

Core types, traits, and error definitions for the IronFix FIX protocol engine.

This crate provides the fundamental building blocks used across all IronFix crates:

• Error types: Unified error handling with thiserror
• Field types: FieldTag, FieldValue, and the FixField trait
• Message types: RawMessage, OwnedMessage, and the FixMessage trait
• Core types: SeqNum, Timestamp, CompID, MsgType

Zero-Copy Design

The core abstractions support both zero-copy borrowed views (for hot-path processing) and owned representations (for storage and cross-thread transfer).