// updateFn must return an updated value.
	// If an error is returned the cached value is not set.
	// Only one caller will call this function at any time, others will be blocking.
	// The returned value can no longer be modified once returned.
	// Should be set before calling Get().
	updateFn func() (T, error)

	// ttl for a cached value.
	ttl time.Duration

	opts Opts

	dst   chan [][]string // result of block decode
	err   error           // any error encountered will be set here
}

// Read - reads single record.
// Once Read is called the previous record should no longer be referenced.
func (r *Reader) Read(dst sql.Record) (sql.Record, error) {
	// If we have have any records left, return these before any error.
	for len(r.current) <= r.recordsRead {
		if r.err != nil {
			return nil, r.err

// yet hold a complete token, for instance if it has no newline while
// scanning lines, a [SplitFunc] can return (0, nil, nil) to signal the
// [Scanner] to read more data into the slice and try again with a
// longer slice starting at the same point in the input.
//
// The function is never called with an empty data slice unless atEOF
// is true. If atEOF is true, however, data may be non-empty and,
// as always, holds unprocessed text.

	// what decoding mechanisms must be applied to obtain the object referenced
	// by the Content-Type header field.
	ContentEncoding string

	// Date and time at which the object is no longer able to be cached
	Expires time.Time

	// Cache-Control - Specifies caching behavior along the request/reply chain
	CacheControl string

	// Specify object storage class
	StorageClass string

	// Requests sent to the server.
	// If the handler is defined with 0 incoming capacity this will be nil.
	// Channel *must* be closed to signal the end of the stream.
	// If the request context is canceled, the stream will no longer process requests.
	Requests chan<- Req
}

// Results returns the results from the remote server one by one.
// If any error is returned by the callback, the stream will be canceled.

	baseOffset int64

	// fileList is a list of files sorted by ename,
	// for use by the Open method.
	fileListOnce sync.Once
	fileList     []fileListEntry
}

// A ReadCloser is a [Reader] that must be closed when no longer needed.
type ReadCloser struct {
	f *os.File
	Reader
}

// A File is a single file in a ZIP archive.
// The file information is in the embedded [FileHeader].

		appendHyphen = true
	}
	if p.sealMD5Fn != nil {
		md5sumCurr = p.sealMD5Fn(md5sumCurr)
	}
	if appendHyphen {
		// Make sure to return etag string upto 32 length, for SSE
		// requests ETag might be longer and the code decrypting the
		// ETag ignores ETag in multipart ETag form i.e <hex>-N
		return hex.EncodeToString(md5sumCurr)[:32] + "-1"
	}
	return hex.EncodeToString(md5sumCurr)
}

		opType:             op,
		replicationRequest: opts.ReplicationRequest,
	}
}

// mustReplicate returns 2 booleans - true if object meets replication criteria and true if replication is to be done in
// a synchronous manner.
func mustReplicate(ctx context.Context, bucket, object string, mopts mustReplicateOptions) (dsc ReplicateDecision) {
	// object layer not initialized we return with no decision.
	if newObjectLayerFn() == nil {
		return

			if rpc != nil {
				ctx, cancel := context.WithTimeout(GlobalContext, 5*time.Second)
				defer cancel()
				c, err := rpc.GetMetacacheListing(ctx, *o)
				if err == nil {
					c.error = "no longer used"
					c.status = scanStateError
					rpc.UpdateMetacacheListing(ctx, *c)
				}
			}
		}()
		o.ID = ""
	}

	// Do listing in-place.
	// Create output for our results.

	// Requests sent to the server.
	// If the handler is defined with 0 incoming capacity this will be nil.
	// Channel *must* be closed to signal the end of the stream.
	// If the request context is canceled, the stream will no longer process requests.
	// Requests sent cannot be used any further by the called.
	Requests chan<- []byte

	muxID uint64
	ctx   context.Context
}

// Send a payload to the remote server.