A standalone crate providing zero-copy data structures (Bank, MarginfiAccount, FeeState, etc.) with bytemuck support and optional Anchor integration. This is the canonical type definition for marginfi's on-chain state, used by the program, CLI, and tests. It is well-isolated, has minimal dependencies, and could be extracted by any project that needs to interact with marginfi accounts or replicate the state model.

A custom forward-allocating bump allocator that replaces Solana's default allocator for the program. It supports heap_pos/heap_restore for memory recycling, useful for compute-heavy operations like risk engine calculations. The allocator is isolated, uses only core/std, and demonstrates non-obvious Solana optimization. Could be extracted into any Solana program that needs to avoid heap reallocation overhead.

A dual-window (hourly/daily) outflow rate limiter implementation using slot-based tracking with sequence numbers. Includes unit tests for edge cases like overflow, empty updates, and unauthorized admin. The logic is generic and encapsulated in a struct with clear methods (record, can_perform, update). Could be extracted as a standalone library for any Solana program needing rate limiting on aggregate outflows.

Provides utilities to validate the ordering of instructions within a transaction, enforcing that certain operations (like liquidation start/end) are paired and that only allowed programs are invoked. This is a critical security pattern for protocols that require multi-step transactions. The implementation is self-contained, uses only solana_program types, and could be reused by any program needing to introspect and constrain transaction layout.