createConnectionPool method
Creates a new connection pool and returns a ConnectionPool wrapper.
The connectionString is used to establish connections in the pool.
The maxSize specifies the maximum number of connections in the pool.
Returns a ConnectionPool on success, null on failure.
Implementation
ConnectionPool? createConnectionPool(String connectionString, int maxSize) {
final poolId = poolCreate(connectionString, maxSize);
if (poolId == 0) return null;
return ConnectionPool(this, poolId);
}