Creating a load job in a project other than the client's project results in error #473
Description
The following code
bq_client = bigquery.Client("project_A")
job = bq_client.load_table_from_json(data, table, job_config=job_config, project="project_B")
would give the error 400 "Value project_B in content does not agree with value project_A. This can happen when a value set through a parameter is inconsistent with a value set in the request."
It seems the upload URL is always set to the client's project.
python-bigquery/google/cloud/bigquery/client.py
Line 2594 in 80944f0