You are designing a SQL Server Integration Services (SSIS) package that uploads a file to a table named Orders in a SQL Azure database. The company's auditing policies have the following requirements:

OnPostExecute is raised immediately after a task or container finishes executing, regardless of success or failure, which satisfies the requirement to write the log entry as soon as the file upload task completes. By attaching an Execute SQL task to this event handler that inserts a row into OrderLog, the audit record is captured in direct response to task completion without requiring additional control flow logic.

OnWarning fires only when a warning is issued during execution, not when a task completes normally, so it would not reliably capture every upload completion.

OnExecStatusChanged fires when the execution status of a task changes at a lower level and is not intended for post-completion audit logging workflows.

OnVariableValueChanged fires when a variable's value is modified, which is unrelated to task completion and would not trigger on upload task completion.