return n - remain, b.readErr()
		}
	}
}

// Read reads data into p.
// It returns the number of bytes read into p.
// The bytes are taken from at most one Read on the underlying [Reader],
// hence n may be less than len(p).
// To read exactly len(p) bytes, use io.ReadFull(b, p).
// If the underlying [Reader] can return a non-zero count with io.EOF,
// then this Read method can do so as well; see the [io.Reader] docs.

	}

	var checksumCombined []byte

	// However, in case of encryption, the persisted part ETags don't match
	// what we have sent to the client during PutObjectPart. The reason is
	// that ETags are encrypted. Hence, the client will send a list of complete
	// part ETags of which non can match the ETag of any part. For example
	//   ETag (client):          30902184f4e62dd8f98f0aaff810c626

	if err != nil {
		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrInvalidRequest), r.URL)
		return
	}
	setEventStreamHeaders(w)

	// Trace Publisher and peer-trace-client uses nonblocking send and hence does not wait for slow receivers.
	// Keep 100k buffered channel.
	// If receiver cannot keep up with that we drop events.
	traceCh := make(chan []byte, 100000)
	peers, _ := newPeerRestClients(globalEndpoints)

			}
			bufIdx := p.readerToBuf[i]
			if p.buf[bufIdx] == nil {
				// Reading first time on this disk, hence the buffer needs to be allocated.
				// Subsequent reads will reuse this buffer.
				p.buf[bufIdx] = make([]byte, p.shardSize)
			}
			// For the last shard, the shardsize might be less than previous shard sizes.
			// Hence the following statement ensures that the buffer size is reset to the right size.

	maxSubscribers int32

	// 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 {

	// sequent of operations:
	// 1) pipe.Write()
	// 2) pipe.Close()
	// Now pipe.Close() can return before the data is read on the other end of the pipe and written to the disk
	// Hence an immediate Read() on the file can return incorrect data.
	if b.canClose != nil {
		b.canClose.Wait()
	}
	return err
}

// newStreamingBitrotWriterBuffer returns streaming bitrot writer implementation.

	if b.Created.IsZero() {
		configs, err := b.getAllLegacyConfigs(ctx, objectAPI)
		if err != nil {
			return b, err
		}

		if len(configs) > 0 {
			// Old bucket without bucket metadata. Hence we migrate existing settings.
			if err = b.convertLegacyConfigs(ctx, objectAPI, configs); err != nil {
				return b, err
			}
		}
	}

	if parse {
		// nothing to update, parse and proceed.

//     single-part object is equal to the object's content MD5.
//     Formatting the SSE-S3 ETag before decryption will result
//     in a random-looking ETag which an S3 client will not accept.
//
// Hence, a caller has to check:
//
//	if method == SSE-S3 {
//	   ETag, err := Decrypt(key, ETag)
//	   if err != nil {
//	   }
//	}
//	ETag = ETag.Format()
func (e ETag) Format() ETag {
	if !e.IsEncrypted() {

			// the end, this is performed by the caller before
			// closing 'w'.
			if err = disk.DisableDirectIO(file); err != nil {
				return written, err
			}

			// buf is not aligned, hence use writeUnaligned()
			// for the remainder
			un, err = w.Write(buf[len(buf)-remain:])
			nw += int64(un)
		}

		if nw > 0 {
			written += nw
		}

		if err != nil {
			return written, err

//
// ### SSE-S3 and KMS
//
// SSE-S3 requires that the KMS provides two functions:
//
//  1. Generate(KeyID) -> (Key, EncKey)
//
//  2. Unseal(KeyID, EncKey) -> Key
//
//  1. Encrypt:
//     Input: KeyID, bucket, object, metadata, object_data
//     -     Key, EncKey := Generate(KeyID)
//     -              IV := Random({0,1}²⁵⁶)
//     -       ObjectKey := SHA256(Key, Random({0,1}²⁵⁶))