lsif-types 
Language Server Index Format (LSIF) types for Rust.
Based on:
- https://microsoft.github.io/language-server-protocol/specifications/lsif/0.4.0/specification/
- https://github.com/microsoft/lsif-node/blob/release/protocol/0.4.3/protocol/src/protocol.ts
Supports LSIF version 0.4.3.