all: add tracking issues for all experimental APIs and make it required

Additionally, make Status*Exception.getTrailers() non experimental

core/src/main/java/io/grpc/ExperimentalApi.java

@@ -53,5 +53,5 @@ public @interface ExperimentalApi {
   /**
    * Context information such as links to discussion thread, tracking issue etc.
    */
-  String value() default "";
+  String value();
 }

core/src/main/java/io/grpc/Metadata.java

@@ -366,7 +366,7 @@ public final class Metadata {
    * Remove all values for the given key without returning them. This is a minor performance
    * optimization if you do not need the previous values.
    */
-  @ExperimentalApi
+  @ExperimentalApi("https://github.com/grpc/grpc-java/issues/4691")
   public <T> void discardAll(Key<T> key) {
     if (isEmpty()) {
       return;

core/src/main/java/io/grpc/SecurityLevel.java

@@ -19,7 +19,7 @@ package io.grpc;
 /**
  * The level of security guarantee in communications.
  */
-@ExperimentalApi
+@ExperimentalApi("https://github.com/grpc/grpc-java/issues/4692")
 public enum SecurityLevel {
   /**
    * No security guarantee.

core/src/main/java/io/grpc/Status.java

@@ -408,7 +408,7 @@ public final class Status {
    *
    * @return the trailers or {@code null} if not found.
    */
-  @ExperimentalApi
+  @ExperimentalApi("https://github.com/grpc/grpc-java/issues/4683")
   public static Metadata trailersFromThrowable(Throwable t) {
     Throwable cause = checkNotNull(t, "t");
     while (cause != null) {

core/src/main/java/io/grpc/StatusException.java

@@ -28,6 +28,11 @@ public class StatusException extends Exception {
   private final Status status;
   private final Metadata trailers;
 
+  /**
+   * Constructs an exception with both a status.  See also {@link Status#asException()}.
+   *
+   * @since 1.0.0
+   */
   public StatusException(Status status) {
     this(status, null);
   }
@@ -35,6 +40,8 @@ public class StatusException extends Exception {
   /**
    * Constructs an exception with both a status and trailers.  See also
    * {@link Status#asException(Metadata)}.
+   *
+   * @since 1.0.0
    */
   public StatusException(Status status, @Nullable Metadata trailers) {
     super(Status.formatThrowableMessage(status), status.getCause());
@@ -44,6 +51,8 @@ public class StatusException extends Exception {
 
   /**
    * Returns the status code as a {@link Status} object.
+   *
+   * @since 1.0.0
    */
   public final Status getStatus() {
     return status;
@@ -51,8 +60,9 @@ public class StatusException extends Exception {
 
   /**
    * Returns the received trailers.
+   *
+   * @since 1.0.0
    */
-  @ExperimentalApi
   public final Metadata getTrailers() {
     return trailers;
   }

core/src/main/java/io/grpc/StatusRuntimeException.java

@@ -29,6 +29,11 @@ public class StatusRuntimeException extends RuntimeException {
   private final Status status;
   private final Metadata trailers;
 
+  /**
+   * Constructs the exception with both a status.  See also {@link Status#asException()}.
+   *
+   * @since 1.0.0
+   */
   public StatusRuntimeException(Status status) {
     this(status, null);
   }
@@ -36,6 +41,8 @@ public class StatusRuntimeException extends RuntimeException {
   /**
    * Constructs the exception with both a status and trailers.  See also
    * {@link Status#asException(Metadata)}.
+   *
+   * @since 1.0.0
    */
   public StatusRuntimeException(Status status, @Nullable Metadata trailers) {
     super(Status.formatThrowableMessage(status), status.getCause());
@@ -45,6 +52,8 @@ public class StatusRuntimeException extends RuntimeException {
 
   /**
    * Returns the status code as a {@link Status} object.
+   *
+   * @since 1.0.0
    */
   public final Status getStatus() {
     return status;
@@ -52,8 +61,9 @@ public class StatusRuntimeException extends RuntimeException {
 
   /**
    * Returns the received trailers.
+   *
+   * @since 1.0.0
    */
-  @ExperimentalApi
   public final Metadata getTrailers() {
     return trailers;
   }

protobuf/src/main/java/io/grpc/protobuf/StatusProto.java

@@ -28,7 +28,7 @@ import io.grpc.protobuf.lite.ProtoLiteUtils;
 import javax.annotation.Nullable;
 
 /** Utility methods for working with {@link com.google.rpc.Status}. */
-@ExperimentalApi
+@ExperimentalApi("https://github.com/grpc/grpc-java/issues/4695")
 public final class StatusProto {
   private StatusProto() {}
 

services/src/main/java/io/grpc/services/HealthStatusManager.java

@@ -27,7 +27,7 @@ import io.grpc.health.v1.HealthCheckResponse.ServingStatus;
  * {@link #getHealthService()} method.
  * The health status manager can update the health statuses of the server.
  */
-@io.grpc.ExperimentalApi
+@io.grpc.ExperimentalApi("https://github.com/grpc/grpc-java/issues/4696")
 public final class HealthStatusManager {
 
   private final HealthServiceImpl healthService;

stub/src/main/java/io/grpc/stub/ClientResponseObserver.java

@@ -22,7 +22,7 @@ import io.grpc.ExperimentalApi;
  * Specialization of {@link StreamObserver} implemented by clients in order to interact with the
  * advanced features of a call such as flow-control.
  */
-@ExperimentalApi
+@ExperimentalApi("https://github.com/grpc/grpc-java/issues/4693")
 public interface ClientResponseObserver<ReqT, RespT> extends StreamObserver<RespT> {
   /**
    * Called by the runtime priot to the start of a call to provide a reference to the

stub/src/main/java/io/grpc/stub/StreamObservers.java

@@ -24,7 +24,7 @@ import java.util.Iterator;
  * Utility functions for working with {@link StreamObserver} and it's common subclasses like
  * {@link CallStreamObserver}.
  */
-@ExperimentalApi
+@ExperimentalApi("https://github.com/grpc/grpc-java/issues/4694")
 public final class StreamObservers {
   /**
    * Copy the values of an {@link Iterator} to the target {@link CallStreamObserver} while properly