v0.1.5

• Add error messages when failed to start.
• Fix bugs.

v0.1.4

• Allow set config path from env FOURTH_CONFIG
• Add config validation
• Other minor refactor

v0.1.3

• Fix problems
• Refactor TCP and KCP tests
• Update README

v0.1.2

• Add KCP support(untested)
• Refactored some code
• Add TCP server test and KCP echo test

v0.1.1

• Use Rust 2021 edition
• Add unit tests