sdk/metric: Record measurements when context is done (#4671)

CONTRIBUTING.md

@@ -591,6 +591,26 @@ this.
 
 [^3]: https://github.com/open-telemetry/opentelemetry-go/issues/3548
 
+### Ignoring context cancellation
+
+OpenTelemetry API implementations need to ignore the cancellation of the context that are
+passed when recording a value (e.g. starting a span, recording a measurement, emitting a log).
+Recording methods should not return an error describing the cancellation state of the context
+when they complete, nor should they abort any work.
+
+This rule may not apply if the OpenTelemetry specification defines a timeout mechanism for
+the method. In that case the context cancellation can be used for the timeout with the
+restriction that this behavior is documented for the method. Otherwise, timeouts
+are expected to be handled by the user calling the API, not the implementation.
+
+Stoppage of the telemetry pipeline is handled by calling the appropriate `Shutdown` method
+of a provider. It is assumed the context passed from a user is not used for this purpose.
+
+Outside of the direct recording of telemetry from the API (e.g. exporting telemetry,
+force flushing telemetry, shutting down a signal provider) the context cancellation
+should be honored. This means all work done on behalf of the user provided context
+should be canceled.
+
 ## Approvers and Maintainers
 
 ### Approvers