public Builder setPageTokenBytes(com.google.protobuf.ByteString value) {
      if (value == null) {
        throw new NullPointerException();
      }
      checkByteStringIsUtf8(value);
      pageToken_ = value;
      bitField0_ |= 0x00000004;
      onChanged();
      return this;
    }
<pre>
A page token, received from a previous `ListCustomClass` call.
Provide this to retrieve the subsequent page.

When paginating, all other parameters provided to `ListCustomClass` must
match the call that provided the page token.
</pre>

<code>string page_token = 3;</code>

@param value The bytes for pageToken to set.
@return This builder for chaining.
java-speech/proto-google-cloud-speech-v1/src/main/java/com/google/cloud/speech/v1/ListCustomClassesRequest.java