title: BigQuery: schema autodetection of JSON couldn't recognize a field appearing later in the JSON input file
body: <p>I found that BigQuery's schema autodetection doesn't recognize a field if that doesn't appear in the beginning of an input JSON file. </p>
  
  <p>I have this field named "details" which is a record type. In the first 2K rows of the JSON input file, this field doesn't have any sub-fields. But then in 2,698 rows of the input file, this field has "report" sub-field for the first time. If I move the line to the top of the JSON file, it works fine. </p>
  
  <p>How can I solve this issue? Explicitly specifying the schema is one way but I am wondering if there is a way to make the auto detection scan more rows or something like that. </p>