Import subscribers from a CSV file asynchronously
Bearer YOUR_API_KEYmultipart/form-data for file uploads.
email - Email address (required)first_name - First namelast_name - Last namephone - Phone number["550e8400-e29b-41d4-a716-446655440000", "660e8400-e29b-41d4-a716-446655440001"]John@Example.com = john@example.com)