Cleanups + fix apiCallTimeout docs.

Author: alextwoods

core/sdk-core/src/main/java/software/amazon/awssdk/core/client/config/ClientOverrideConfiguration.java

@@ -288,6 +288,9 @@ public Optional<ScheduledExecutorService> scheduledExecutorService() {
      * execution except for marshalling. This includes request handler execution, all HTTP requests including retries,
      * unmarshalling, etc. This value should always be positive, if present.
      *
+     * <p>Because this window is narrower than the API call as a whole, the reported
+     * {@link software.amazon.awssdk.core.metrics.CoreMetric#API_CALL_DURATION} metric can exceed this timeout.
+     *
      * <p>The api call timeout feature doesn't have strict guarantees on how quickly a request is aborted when the
      * timeout is breached. The typical case aborts the request within a few milliseconds but there may occasionally be
      * requests that don't get aborted until several seconds after the timer has been breached. Because of this, the client
@@ -613,6 +616,9 @@ default Builder retryStrategy(Consumer<RetryStrategy.Builder<?, ?>> configurator
          * entire client execution except for marshalling. This includes request handler execution, all HTTP requests including
          * retries, unmarshalling, etc. This value should always be positive, if present.
          *
+         * <p>Because this window is narrower than the API call as a whole, the reported
+         * {@link software.amazon.awssdk.core.metrics.CoreMetric#API_CALL_DURATION} metric can exceed this timeout.
+         *
          * <p>The api call timeout feature doesn't have strict guarantees on how quickly a request is aborted when the
          * timeout is breached. The typical case aborts the request within a few milliseconds but there may occasionally be
          * requests that don't get aborted until several seconds after the timer has been breached. Because of this, the client

core/sdk-core/src/main/java/software/amazon/awssdk/core/internal/util/MetricUtils.java

@@ -31,7 +31,6 @@
 import software.amazon.awssdk.http.HttpMetric;
 import software.amazon.awssdk.http.SdkHttpFullRequest;
 import software.amazon.awssdk.http.SdkHttpFullResponse;
-import software.amazon.awssdk.http.SdkHttpRequest;
 import software.amazon.awssdk.metrics.MetricCollector;
 import software.amazon.awssdk.metrics.NoOpMetricCollector;
 import software.amazon.awssdk.metrics.SdkMetric;

core/sdk-core/src/main/java/software/amazon/awssdk/core/metrics/CoreMetric.java

@@ -72,6 +72,10 @@ public final class CoreMetric {
      *
      * <p>The relation is approximate because several steps inside the window have no metric of their own including
      * request compression and checksum computation.
+     *
+     * <p>This is not bounded by a configured
+     * {@link software.amazon.awssdk.core.client.config.ClientOverrideConfiguration.Builder#apiCallTimeout(Duration)
+     * apiCallTimeout}, which covers a narrower window that excludes marshalling and the interceptors.
      */
     public static final SdkMetric<Duration> API_CALL_DURATION =
         metric("ApiCallDuration", Duration.class, MetricLevel.INFO);