@java.lang.Override
    public Builder mergeFrom(
        com.google.protobuf.CodedInputStream input,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
        throws java.io.IOException {
      if (extensionRegistry == null) {
        throw new java.lang.NullPointerException();
      }
      try {
        boolean done = false;
        while (!done) {
          int tag = input.readTag();
          switch (tag) {
            case 0:
              done = true;
              break;
            case 10:
              {
                service_ = input.readStringRequireUtf8();
                bitField0_ |= 0x00000001;
                break;
              } // case 10
            case 18:
              {
                version_ = input.readStringRequireUtf8();
                bitField0_ |= 0x00000002;
                break;
              } // case 18
            case 26:
              {
                instance_ = input.readStringRequireUtf8();
                bitField0_ |= 0x00000004;
                break;
              } // case 26
            case 34:
              {
                host_ = input.readStringRequireUtf8();
                bitField0_ |= 0x00000008;
                break;
              } // case 34
            default:
              {
                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
                  done = true; // was an endgroup tag
                }
                break;
              } // default:
          } // switch (tag)
        } // while (!done)
      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
        throw e.unwrapIOException();
      } finally {
        onChanged();
      } // finally
      return this;
    }
<pre>
App Engine Routing.

Defines routing characteristics specific to App Engine - service, version,
and instance.

For more information about services, versions, and instances see
[An Overview of App
Engine](https://cloud.google.com/appengine/docs/python/an-overview-of-app-engine),
[Microservices Architecture on Google App
Engine](https://cloud.google.com/appengine/docs/python/microservices-on-app-engine),
[App Engine Standard request
routing](https://cloud.google.com/appengine/docs/standard/python/how-requests-are-routed),
and [App Engine Flex request
routing](https://cloud.google.com/appengine/docs/flexible/python/how-requests-are-routed).
</pre>

Protobuf type {@code google.cloud.tasks.v2beta2.AppEngineRouting}
java-tasks/proto-google-cloud-tasks-v2beta2/src/main/java/com/google/cloud/tasks/v2beta2/AppEngineRouting.java