Move implementation details of the Observed Timestamp to the Log SDK (#4482)

Author: XSAM

CHANGELOG.md

@@ -61,6 +61,8 @@ release.
   ([#4463](https://github.com/open-telemetry/opentelemetry-specification/pull/4463))
 - Stabilize `EventName`.
   ([#4475](https://github.com/open-telemetry/opentelemetry-specification/pull/4475))
+- Move implementation details of the `Observed Timestamp` to the Log SDK.
+  ([#4482](https://github.com/open-telemetry/opentelemetry-specification/pull/4482))
 
 ### Baggage
 

specification/logs/api.md

@@ -112,8 +112,7 @@ The effect of calling this API is to emit a `LogRecord` to the processing pipeli
 The API MUST accept the following parameters:
 
 - [Timestamp](./data-model.md#field-timestamp) (optional)
-- [Observed Timestamp](./data-model.md#field-observedtimestamp) (optional). If unspecified the
-  implementation SHOULD set it equal to the current time.
+- [Observed Timestamp](./data-model.md#field-observedtimestamp) (optional)
 - The [Context](../context/README.md) associated with the `LogRecord`.
   When implicit Context is supported, then this parameter SHOULD be optional and
   if unspecified then MUST use current Context.

specification/logs/sdk.md

@@ -16,6 +16,7 @@
   * [ForceFlush](#forceflush)
 - [Logger](#logger)
   * [LoggerConfig](#loggerconfig)
+  * [Emit a LogRecord](#emit-a-logrecord)
   * [Enabled](#enabled)
 - [Additional LogRecord interfaces](#additional-logrecord-interfaces)
   * [ReadableLogRecord](#readablelogrecord)
@@ -192,6 +193,11 @@ It consists of the following parameters:
   necessary for implementations to ensure that changes to `disabled` are
   immediately visible to callers of `Enabled`.
 
+### Emit a LogRecord
+
+If [Observed Timestamp](./data-model.md#field-observedtimestamp) is unspecified,
+the implementation SHOULD set it equal to the current time.
+
 ### Enabled
 
 **Status**: [Development](../document-status.md)