Context.Storage deprecated method attach() removed, doAttach() made abstract (grpc#10379)

Author: tonyjongyoonan

api/src/context/java/io/grpc/Context.java

@@ -999,16 +999,6 @@ public String toString() {
    * subject to change.
    */
   public abstract static class Storage {
-    /**
-     * Unused.
-     *
-     * @deprecated This is an old API that is no longer used.
-     */
-    @Deprecated
-    public void attach(Context toAttach) {
-      throw new UnsupportedOperationException("Deprecated. Do not call.");
-    }
-
     /**
      * Implements {@link io.grpc.Context#attach}.
      *
@@ -1022,13 +1012,7 @@ public void attach(Context toAttach) {
      *        as the {@code toRestore} parameter. {@code null} is a valid return value, but see
      *        caution note.
      */
-    public Context doAttach(Context toAttach) {
-      // This is a default implementation to help migrate existing Storage implementations that
-      // have an attach() method but no doAttach() method.
-      Context current = current();
-      attach(toAttach);
-      return current;
-    }
+    public abstract Context doAttach(Context toAttach);
 
     /**
      * Implements {@link io.grpc.Context#detach}.