WalReceiverTimeout = Timeout.InfiniteTimeSpan causes immediate TimeoutException during StartReplication in Npgsql 10

Description

Setting WalReceiverTimeout = Timeout.InfiniteTimeSpan on a LogicalReplicationConnection causes an immediate TimeoutException during StartReplication in Npgsql 10.0.1. The same code worked correctly in Npgsql 9.0.4.

This appears to be a consequence of the Npgsql 10 breaking change where Timeout.InfiniteTimeSpan is now correctly interpreted as infinite (previously it was misinterpreted as TimeSpan.Zero). However, passing an infinite wal_receiver_timeout to Postgres during the START_REPLICATION handshake causes Postgres to immediately close the connection, which Npgsql surfaces as a TimeoutException.

Repro

const string connectionString = "Host=localhost;Port=5432;Database=YOUR_DB;Username=YOUR_USER;Password=YOUR_PASSWORD";
const string publicationName = "YOUR_PUBLICATION"; // Must already exist
const string slotName = "test_repro_slot";

try
{
    await using var conn = new LogicalReplicationConnection(connectionString);
    conn.WalReceiverTimeout = Timeout.InfiniteTimeSpan; // <---- this line causes the issue

    await conn.Open();

    var slot = await conn.CreatePgOutputReplicationSlot(slotName, true);

    await foreach (var message in conn.StartReplication(slot,
                       new PgOutputReplicationOptions(publicationName, PgOutputProtocolVersion.V2),
                       CancellationToken.None))
    {
        Console.WriteLine($"Received message type: {message.GetType().Name}");
        conn.SetReplicationStatus(message.WalEnd);
    }
}
catch (Exception e)
{
    Console.WriteLine(e);
}
Console.Read();

Expected behavior

The replication stream connects and waits indefinitely for messages, consistent with Timeout.InfiniteTimeSpan semantics.

Actual behavior

Npgsql.NpgsqlException: Exception while reading from stream
 ---> System.TimeoutException: Timeout during reading attempt
   at Npgsql.Internal.NpgsqlConnector.ReadMessageLong(...)
   at Npgsql.Replication.ReplicationConnection.StartReplicationInternal(...)

Workaround

Use TimeSpan.Zero instead of Timeout.InfiniteTimeSpan.

Environment