https://learn.microsoft.com/en-gb/dotnet/api/system.data.sqlclient.sqlcommand.beginexecutereader?view=netframework-4.8
SqlCommand.BeginExecuteReader Method (System.Data.SqlClient) | Microsoft Learn
Initiates the asynchronous execution of the Transact-SQL statement or stored procedure that is described by this SqlCommand, and retrieves one or more result...
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