code: public static ExternalTableDefinition of(String sourceUri, Schema schema, FormatOptions format) {
      return newBuilder(sourceUri, schema, format).build();
    }
docs: Creates an ExternalTableDefinition object.
  
  @param sourceUri a fully-qualified URI that points to your data in Google Cloud Storage. The
  URI can contain one '*' wildcard character that must come after the bucket's name. Size
  limits related to load jobs apply to external data sources.
  @param schema the schema for the external data
  @param format the source format of the external data
  @return an ExternalTableDefinition object given source URIs, schema and format
  @see <a href="https://cloud.google.com/bigquery/loading-data-into-bigquery#quota">Quota</a>
  @see <a
  href="https://cloud.google.com/bigquery/docs/reference/v2/tables#externalDataConfiguration.sourceFormat">
  Source Format</a>