Allow logs to be mutated by LogProcessor

[jack-berg]

Implements spec PR#2681.
Resolves #4550.

Summary:

• Rename LogBuilder to LogRecordBuilder to better reflect the data model and the naming we can expect to see in the log appender / event API.
• Change LogProcessor#emit to onEmit to better match trace SDK.
• Introduce ReadWriteLogRecord interface, which is passed to LogProcessor#onEmit instead of LogData. This is roughly aligned with tracing. However, in tracing ReadWriteSpan extends Span and ReadableSpan. This separation of Span for updating and ReadableSpan for reading isn't needed in the log SDK because there isn't a LogProcessor onStart and onEnd which have different read / write semantics.
• ReadWriteLogRecord has a toLogData() method, which is called by the simple and batch log processor to convert the data to an immutable representation before calling LogExporter#export(Collection<LogData>).
• Add single attribute setters (setAttribute(AttributeKey<T>, T)), rename multi attribute setter to setAllAttributes(Attributes) to mirror tracing

[codecov]

Codecov Report

Merging #4643 (caff25a) into main (77be2e0) will decrease coverage by 0.01%.
The diff coverage is 83.33%.

@@             Coverage Diff              @@
##               main    #4643      +/-   ##
============================================
- Coverage     90.08%   90.06%   -0.02%     
- Complexity     5074     5085      +11     
============================================
  Files           584      586       +2     
  Lines         15667    15707      +40     
  Branches       1504     1507       +3     
============================================
+ Hits          14114    14147      +33     
- Misses         1100     1103       +3     
- Partials        453      457       +4     

Impacted Files	Coverage Δ
...n/java/io/opentelemetry/sdk/logs/LogProcessor.java	85.71% <ø> (ø)
...lemetry/sdk/logs/SdkLogEmitterProviderBuilder.java	100.00% <ø> (ø)
...va/io/opentelemetry/sdk/logs/LogRecordBuilder.java	60.00% <60.00%> (ø)
.../opentelemetry/sdk/logs/SdkReadWriteLogRecord.java	80.00% <80.00%> (ø)
...entelemetry/sdk/logs/export/BatchLogProcessor.java	88.72% <85.71%> (ø)
...io/opentelemetry/sdk/logs/SdkLogRecordBuilder.java	97.50% <92.85%> (ø)
...a/io/opentelemetry/sdk/logs/MultiLogProcessor.java	90.90% <100.00%> (ø)
...va/io/opentelemetry/sdk/logs/NoopLogProcessor.java	100.00% <100.00%> (ø)
.../java/io/opentelemetry/sdk/logs/SdkLogEmitter.java	100.00% <100.00%> (ø)
...ntelemetry/sdk/logs/export/SimpleLogProcessor.java	88.57% <100.00%> (ø)
... and 1 more

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[jack-berg]

Hey @jkwatson - wondering what your thoughts are about trying to get this in before the 1.17.0 release. It technically depends on this spec PR, but I think its extremely likely that the spec goes in this direction and that its current state of not allowing mutable logs is accidental. Additionally, both the spec and the sdk are experimental so I think its ok for us to experiment (within reason!).

[jkwatson]

I'm fine with this. It'll be interesting to see how it ends up differing from the final spec, but we'll update as appropriate before stabilization.

[jack-berg]

@trask for now the only thing you can mutate is log attributes. I plan on adding getters / setters on here in the future, but wondering if this is sufficient for your short term requirements.

[trask]

yes, this is exactly what I need for now 👍