// The WriteCloser's Close method must be used to flush pending data to w.
// The Compressor itself must be safe to invoke from multiple goroutines
// simultaneously, but each returned writer will be used only by
// one goroutine at a time.
type Compressor func(w io.Writer) (io.WriteCloser, error)

// A Decompressor returns a new decompressing reader, reading from r.
// The [io.ReadCloser]'s Close method must be used to release associated resources.

	BuildID    string    `json:",omitempty"`
	TimeReady  time.Time `json:",omitempty"`
	TimeStart  time.Time `json:",omitempty"`
	TimeDone   time.Time `json:",omitempty"`

	Cmd     []string      // `json:",omitempty"`
	CmdReal time.Duration `json:",omitempty"`
	CmdUser time.Duration `json:",omitempty"`
	CmdSys  time.Duration `json:",omitempty"`
}

// cacheKey is the key for the action cache.

package main

import (
	"encoding/json"
	"fmt"
	"os"
	"time"
)

func truncateLike(t, p time.Time) time.Time {
	nano := p.UnixNano()
	d := 1 * time.Nanosecond
	for nano%int64(d) == 0 && d < 1*time.Second {
		d *= 10
	}
	for nano%int64(d) == 0 && d < 2*time.Second {
		d *= 2
	}
	return t.Truncate(d)
}

func main() {
	var t1 time.Time
	b1, err := os.ReadFile(os.Args[1])
	if err != nil {

written by hand — loosely derived from golang.org/x/crypto/internal/subtle,
but splitting the internal package across a module boundary

-- .mod --
module golang.org/x/internal
-- .info --
{"Version":"v0.1.0","Name":"","Short":"","Time":"2018-07-25T17:24:00Z"}
-- go.mod --
module golang.org/x/internal
-- subtle/aliasing.go --
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style

	// does not always result in the PAX format being chosen, which
	// causes a 1KiB increase to every header.
	if tw.hdr.Format == FormatUnknown {
		tw.hdr.ModTime = tw.hdr.ModTime.Round(time.Second)
		tw.hdr.AccessTime = time.Time{}
		tw.hdr.ChangeTime = time.Time{}
	}

	allowedFormats, paxHdrs, err := tw.hdr.allowedFormats()
	switch {
	case allowedFormats.has(FormatUSTAR):
		tw.err = tw.writeUSTARHeader(&tw.hdr)
		return tw.err

pkg net/smtp, method (*Client) Noop() error
pkg os, func IsTimeout(error) bool
pkg os, method (*File) SetDeadline(time.Time) error
pkg os, method (*File) SetReadDeadline(time.Time) error
pkg os, method (*File) SetWriteDeadline(time.Time) error
pkg os, method (*PathError) Timeout() bool
pkg os, method (*SyscallError) Timeout() bool
pkg os, var ErrNoDeadline error

	testenv.MustHaveGoBuild(t)
	if !*fixDocs {
		t.Parallel()
	}

	// We run 'go help documentation' as a subprocess instead of
	// calling help.Help directly because it may be sensitive to
	// init-time configuration
	cmd := testenv.Command(t, testGo, "help", "documentation")
	// Unset GO111MODULE so that the 'go get' section matches
	// the default 'go get' implementation.
	cmd.Env = append(cmd.Environ(), "GO111MODULE=")

Constructed by hand.
(derived from rsc.io/quote@e7a685a342, but without an explicit go.mod file.)

-- .mod --
module "not-rsc.io/quote"
-- .info --
{"Version":"v0.1.0-nomod","Time":"2018-02-14T00:51:33Z"}
-- quote.go --
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package quote collects pithy sayings.

rsc.io/quote@v1.2.1

-- .mod --
module "rsc.io/quote"
-- .info --
{"Version":"v1.2.1","Name":"5c1f03b64ab7aa958798a569a31924655dc41e76","Short":"5c1f03b64ab7","Time":"2018-02-14T00:54:20Z"}
-- go.mod --
module "rsc.io/quote"
-- quote.go --
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package quote collects pithy sayings.

		p.To.Name = obj.NAME_EXTERN
		p.To.Sym = ir.Syms.Duffzero
		p.To.Offset = 8 * (128 - cnt/int64(types.PtrSize))
		return p
	}

	// Loop, zeroing pointer width bytes at a time.
	// ADD	$(off), SP, T0
	// ADD	$(cnt), T0, T1
	// loop:
	// 	MOV	ZERO, (T0)
	// 	ADD	$Widthptr, T0
	//	BNE	T0, T1, loop
	p = pp.Append(p, riscv.AADD, obj.TYPE_CONST, 0, off, obj.TYPE_REG, riscv.REG_T0, 0)