v1.3.0

Bug Fixes

• Fixed data race in test suite when accessing mock SMTP server messages
• Fixed pool.Close() race condition that could cause a panic on concurrent use
• Fixed releaseConnection panicking when writing to a closed channel
• Fixed SetRateLimit leaking goroutines when called multiple times

Improvements

• Added Close() method to Mail for explicit resource cleanup (pool connections and rate limiter)
• Email validation regex is now compiled once at package level instead of on every call