var wqtErr topology.WaitQueueTimeoutError
if errors.As(err, &wqtErr) {
    // Handle waitQueue timeout error
}

// IsWaitQueueTimeout returns true if err is a wait queue timeout error, which occurs when
// checking out a connection from the pool times out.
func IsWaitQueueTimeout(err error) bool {
	return errors.As(err, &topology.WaitQueueTimeoutError{})
}

// WaitQueueTimeoutError is returned when a connection checkout from the pool times out.
type WaitQueueTimeoutError struct {
    Wrapped              error         // The underlying timeout error
    MaxPoolSize          uint64        // The maximum pool size
    TotalConnections     int           // Total number of connections in the pool
    AvailableConnections int           // Number of idle connections
    WaitDuration         time.Duration // How long the operation waited

    // For load-balanced mode only
    PinnedCursorConnections      *uint64
    PinnedTransactionConnections *uint64

    // Internal flag for error message formatting
    wrappedMsgOnly bool
}

func (w WaitQueueTimeoutError) Error() string {
    // If wrapped by wrapErrors, just return wrapped error message
    if w.wrappedMsgOnly {
        return w.Wrapped.Error()
    }
    
    // Otherwise build the full error message
    // ... (delegate to wrapped error's Error method or build similar format)
}

func (w WaitQueueTimeoutError) Unwrap() error {
    return w.Wrapped
}