Refactoring

Tests

Make tests for all message flow scenarios.
Errors while validation query processing while getting connection in two cases (pool and plain connectible)
Errors while authentication
Errors while simple query process
Errors while extended query process
Multiple result sets test
Connection pool statements eviction and duplicated statements
Termination process test
Prepared statement eviction test
Auto rollback transaction review
Ssl interaction test
Notifications test
Transactions general test
Connection pool general test
Queries pipelining vs errors test