current.First = o.name
			}

			if n >= w.blockEntries-1 {
				finishBlock()
				n = 0
			}
			n++

			w.streamErr = block.write(o)
			if w.streamErr != nil {
				continue
			}
			current.Last = o.name
		}
		if n > 0 || current.n == 0 {
			current.EOS = true
			finishBlock()
		}
	}()
	return &w
}

// Close the stream.