presto-example-http/src/main/java/io/prestosql/plugin/example/ExampleMetadata.java/ExampleMetadata/getTableMetadata
class ExampleMetadata:    private ConnectorTableMetadata getTableMetadata(SchemaTableName tableName)
    {
        if (!listSchemaNames().contains(tableName.getSchemaName())) {
            return null;
        }

        ExampleTable table = exampleClient.getTable(tableName.getSchemaName(), tableName.getTableName());
        if (table == null) {
            return null;
        }

        return new ConnectorTableMetadata(tableName, table.getColumnsMetadata());
    }