s = s[:maxTraceStringLen]
	}

	lock(&t.lock)
	w := unsafeTraceWriter(gen, t.buf)

	// Ensure we have a place to write to.
	var flushed bool
	w, flushed = w.ensure(2 + 2*traceBytesPerNumber + len(s) /* traceEvStrings + traceEvString + ID + len + string data */)
	if flushed {
		// Annotate the batch as containing strings.
		w.byte(byte(traceEvStrings))
	}

	// Write out the string.
	w.byte(byte(traceEvString))

	bytesMarked uint64

	// Heap scan work performed on this gcWork. This is aggregated into
	// gcController by dispose and may also be flushed by callers.
	// Other types of scan work are flushed immediately.
	heapScanWork int64

	// flushedWork indicates that a non-empty work buffer was
	// flushed to the global work list since the last gcMarkDone
	// termination check. Specifically, this indicates that this

	// bound is pretty loose, but avoids counting
	// lots of varint sizes.
	//
	// Add 1 because we might also write a traceAllocFreeTypesBatch byte.
	var flushed bool
	w, flushed = w.ensure(1 + maxBytes)
	if flushed {
		// Annotate the batch as containing types.
		w.byte(byte(traceAllocFreeTypesBatch))
	}

	// Emit type.
	w.varint(uint64(node.id))
	w.varint(uint64(uintptr(unsafe.Pointer(typ))))

func traceSnapshotMemory(gen uintptr) {
	assertWorldStopped()

	// Write a batch containing information that'll be necessary to
	// interpret the events.
	var flushed bool
	w := unsafeTraceExpWriter(gen, nil, traceExperimentAllocFree)
	w, flushed = w.ensure(1 + 4*traceBytesPerNumber)
	if flushed {
		// Annotate the batch as containing additional info.
		w.byte(byte(traceAllocFreeInfoBatch))
	}

	// Emit info.

		}

		// Write out a trace event.
		w := unsafeTraceWriter(gen, trace.cpuBuf[gen%2])

		// Ensure we have a place to write to.
		var flushed bool
		w, flushed = w.ensure(2 + 5*traceBytesPerNumber /* traceEvCPUSamples + traceEvCPUSample + timestamp + g + m + p + stack ID */)
		if flushed {
			// Annotate the batch as containing strings.
			w.byte(byte(traceEvCPUSamples))
		}

		// Add the stack to the table.

	return traceExpWriter{traceWriter{traceLocker: traceLocker{gen: gen}, traceBuf: buf}, exp}
}

// ensure makes sure that at least maxSize bytes are available to write.
//
// Returns whether the buffer was flushed.
func (w traceExpWriter) ensure(maxSize int) (traceExpWriter, bool) {
	refill := w.traceBuf == nil || !w.available(maxSize)
	if refill {
		w.traceWriter = w.traceWriter.refill(w.exp)
	}
	return w, refill
}

	n, z.err = z.compressor.Write(p)
	return n, z.err
}

// Flush flushes any pending compressed data to the underlying writer.
//
// It is useful mainly in compressed network protocols, to ensure that
// a remote reader has enough data to reconstruct a packet. Flush does
// not return until the data has been written. If the underlying
// writer returns an error, Flush returns that error.
//

	// Estimate the size of this record. This
	// bound is pretty loose, but avoids counting
	// lots of varint sizes.
	//
	// Add 1 because we might also write traceEvStacks.
	var flushed bool
	w, flushed = w.ensure(1 + maxBytes)
	if flushed {
		w.byte(byte(traceEvStacks))
	}

	// Emit stack event.
	w.byte(byte(traceEvStack))
	w.varint(uint64(node.id))
	w.varint(uint64(len(frames)))

	// to avoid spilling mark bits into the *next* GC cycle.
	sg := mheap_.sweepgen
	flushGen := c.flushGen.Load()
	if flushGen == sg {
		return
	} else if flushGen != sg-2 {
		println("bad flushGen", flushGen, "in prepareForSweep; sweepgen", sg)
		throw("bad flushGen")
	}
	c.releaseAll()
	stackcache_clear(c)
	c.flushGen.Store(mheap_.sweepgen) // Synchronizes with gcStart

// complete for formatting purposes.
func (b *Writer) Flush() error {
	return b.flush()
}

// flush is the internal version of Flush, with a named return value which we
// don't want to expose.
func (b *Writer) flush() (err error) {
	defer b.handlePanic(&err, "Flush")
	b.flushNoDefers()
	return nil
}

// flushNoDefers is like flush, but without a deferred handlePanic call. This