return NewReaderSize(rd, defaultBufSize)
}

// Size returns the size of the underlying buffer in bytes.
func (b *Reader) Size() int { return len(b.buf) }

// Reset discards any buffered data, resets all state, and switches
// the buffered reader to read from r.
// Calling Reset on the zero value of [Reader] initializes the internal buffer
// to the default size.
// Calling b.Reset(b) (that is, resetting a [Reader] to itself) does nothing.

package deadlineconn

import (
	"net"
	"time"
)

const updateInterval = 250 * time.Millisecond

// DeadlineConn - is a generic stream-oriented network connection supporting buffered reader and read/write timeout.
type DeadlineConn struct {
	net.Conn
	readDeadline  time.Duration // sets the read deadline on a connection.
	readSetAt     time.Time

   * Prepares the HTTP headers and sends them to the server.
   *
   * For streaming requests with a body, headers must be prepared **before** the output stream has
   * been written to. Otherwise the body would need to be buffered!
   *
   * For non-streaming requests with a body, headers must be prepared **after** the output stream
   * has been written to and closed. This ensures that the `Content-Length` header field receives
   * the proper value.

  val requestBody: BufferedSource
  val responseBody: BufferedSink

  /**
   * Terminate the stream so that no further data is transmitted or received. Note that
   * [requestBody] may return data after this call; that is the buffered data received before this
   * stream was canceled.
   *
   * This does nothing if [requestBody] and [responseBody] are already closed.
   *

   *
   * @throws IOException if an I/O error occurs while opening the stream
   */
  public abstract OutputStream openStream() throws IOException;

  /**
   * Opens a new buffered {@link OutputStream} for writing to this sink. The returned stream is not
   * required to be a {@link BufferedOutputStream} in order to allow implementations to simply

     * 
     * Closing the context should cancel a pending notify request, but that does not seem to work reliable in all
     * implementations.
     * 
     * Changes in between these calls (as long as the file is open) are buffered by the server, so iteratively calling
     * this method should provide all changes (size of that buffer can be adjusted through
     * {@link jcifs.Configuration#getNotifyBufferSize()}).

If you want to block when reading or writing, you must enable it:

```go
	rb := ringbuffer.New(1024).SetBlocking(true)
```

Enabling blocking will cause the ring buffer to behave like a buffered [io.Pipe](https://pkg.go.dev/io#Pipe).

Regular Reads will block until data is available, but not wait for a full buffer. 

		t.Error("expected flush error, got nil")
	}
	if _, err := wr.ReadFrom(strings.NewReader("test2")); err == nil {
		t.Fatal("expected error, got nil")
	}
	if buffered := wr.Buffered(); buffered != wantBuffered {
		t.Fatalf("Buffered = %v; want %v", buffered, wantBuffered)
	}
}

func BenchmarkReaderCopyOptimal(b *testing.B) {
	// Optimal case is where the underlying reader implements io.WriterTo

					select {
					case <-ctx.Done():
						return nil
					case out <- toSend:
					}
				}
				return nil
			},

			Subroute:    "some-subroute",
			OutCapacity: 1, // Only one message buffered.
			InCapacity:  0,
		}))
		errFatal(err)
	}
	const payloadSize = 512
	rng := rand.New(rand.NewSource(time.Now().UnixNano()))
	payload := make([]byte, payloadSize)
	_, err = rng.Read(payload)

	// not atomics:
	subs []*Sub[T]
	sync.RWMutex
}

// Publish message to the subscribers.
// Note that publish is always non-blocking send so that we don't block on slow receivers.
// Hence receivers should use buffered channel so as not to miss the published events.
func (ps *PubSub[T, M]) Publish(item T) {
	ps.RLock()
	defer ps.RUnlock()
	for _, sub := range ps.subs {