@java.lang.Override
  public final boolean isInitialized() {
    byte isInitialized = memoizedIsInitialized;
    if (isInitialized == 1) return true;
    if (isInitialized == 0) return false;

    memoizedIsInitialized = 1;
    return true;
  }
<pre>
Specifies the input document's mime_type.

If not specified it will be determined using the file extension for
gcs_source provided files. For a file provided through bytes content the
mime_type must be provided.
Currently supported mime types are:
- application/pdf
- application/vnd.openxmlformats-officedocument.wordprocessingml.document
- application/vnd.openxmlformats-officedocument.presentationml.presentation
- application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
</pre>

<code>string mime_type = 4;</code>

@return The bytes for mimeType.
java-translate/proto-google-cloud-translate-v3beta1/src/main/java/com/google/cloud/translate/v3beta1/DocumentInputConfig.java