Modern C#

.NET 8+, nullable enabled, async-first, records for data.

Async Patterns

Always use async/await for I/O. Always pass CancellationToken:

public async Task<User?> GetUserAsync(
    int id,
    CancellationToken cancellationToken = default)
{
    using var connection = await _factory
        .CreateConnectionAsync(cancellationToken)
        .ConfigureAwait(false);