log: Add Record.Clone

[arjun7579]

Fixes #6986

Add the Clone() method to the log.Record type.
It returns a copy of the record with no shared state, allowing both the original and the clone to be modified independently.

The back slice is cloned using slices.Clone to avoid shared references.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: arjun7579 / name: arjun (8d9ecec, 537ea35)

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 82.7%. Comparing base (687c3f5) to head (8d9ecec).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
log/record.go	0.0%	4 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #6991     +/-   ##
=======================================
- Coverage   82.7%   82.7%   -0.1%     
=======================================
  Files        262     262             
  Lines      24325   24329      +4     
=======================================
- Hits       20140   20136      -4     
- Misses      3810    3818      +8     
  Partials     375     375             

Files with missing lines	Coverage Δ
log/record.go	91.6% <0.0%> (-8.4%)	⬇️

... and 2 files with indirect coverage changes

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[pellared]

From https://github.com/open-telemetry/opentelemetry-go/blob/main/CONTRIBUTING.md:

update CHANGELOG.md

Each functionality should be covered by tests.

This should help you:

• opentelemetry-go/sdk/log/record_test.go

  Lines 140 to 204 in e4c84b9

  	func TestRecordClone(t *testing.T) {
  	now0 := time.Now()
  	sev0 := log.SeverityInfo
  	text0 := "text"
  	val0 := log.BoolValue(true)
  	attr0 := log.Bool("0", true)
  	traceID0 := trace.TraceID([16]byte{1})
  	spanID0 := trace.SpanID([8]byte{1})
  	flag0 := trace.FlagsSampled
  	r0 := new(Record)
  	r0.SetTimestamp(now0)
  	r0.SetObservedTimestamp(now0)
  	r0.SetSeverity(sev0)
  	r0.SetSeverityText(text0)
  	r0.SetBody(val0)
  	r0.SetAttributes(attr0)
  	r0.SetTraceID(traceID0)
  	r0.SetSpanID(spanID0)
  	r0.SetTraceFlags(flag0)
  	now1 := now0.Add(time.Second)
  	sev1 := log.SeverityDebug
  	text1 := "string"
  	val1 := log.IntValue(1)
  	attr1 := log.Int64("1", 2)
  	traceID1 := trace.TraceID([16]byte{2})
  	spanID1 := trace.SpanID([8]byte{2})
  	flag1 := trace.TraceFlags(2)
  	r1 := r0.Clone()
  	r1.SetTimestamp(now1)
  	r1.SetObservedTimestamp(now1)
  	r1.SetSeverity(sev1)
  	r1.SetSeverityText(text1)
  	r1.SetBody(val1)
  	r1.SetAttributes(attr1)
  	r1.SetTraceID(traceID1)
  	r1.SetSpanID(spanID1)
  	r1.SetTraceFlags(flag1)
  	assert.Equal(t, now0, r0.Timestamp())
  	assert.Equal(t, now0, r0.ObservedTimestamp())
  	assert.Equal(t, sev0, r0.Severity())
  	assert.Equal(t, text0, r0.SeverityText())
  	assert.True(t, val0.Equal(r0.Body()))
  	assert.Equal(t, traceID0, r0.TraceID())
  	assert.Equal(t, spanID0, r0.SpanID())
  	assert.Equal(t, flag0, r0.TraceFlags())
  	r0.WalkAttributes(func(kv log.KeyValue) bool {
  	return assert.Truef(t, kv.Equal(attr0), "%v != %v", kv, attr0)
  	})
  	assert.Equal(t, now1, r1.Timestamp())
  	assert.Equal(t, now1, r1.ObservedTimestamp())
  	assert.Equal(t, sev1, r1.Severity())
  	assert.Equal(t, text1, r1.SeverityText())
  	assert.True(t, val1.Equal(r1.Body()))
  	assert.Equal(t, traceID1, r1.TraceID())
  	assert.Equal(t, spanID1, r1.SpanID())
  	assert.Equal(t, flag1, r1.TraceFlags())
  	r1.WalkAttributes(func(kv log.KeyValue) bool {
  	return assert.Truef(t, kv.Equal(attr1), "%v != %v", kv, attr1)
  	})
  	}

Also linter failed with:

Error: log/record.go:146:1: File is not properly formatted (gofumpt)