@java.lang.Override
    public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
      if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(accountEmail_)) {
        com.google.protobuf.GeneratedMessageV3.writeString(output, 1, accountEmail_);
      }
      if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(subjectId_)) {
        com.google.protobuf.GeneratedMessageV3.writeString(output, 2, subjectId_);
      }
      getUnknownFields().writeTo(output);
    }
<pre>
Unique identifier for the service account.
</pre>

<code>string subject_id = 2;</code>

@return The bytes for subjectId.
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferTypes.java