/// <summary>
/// Looks up the specified key in the <see cref="MDC"/>.
/// </summary>
/// <param name="key">The key to lookup.</param>
/// <returns>
/// The value associated with the key, or <c>null</c> if the key was not found.
/// </returns>
public string LookupMappedContext(string key)
{
if (m_data.MDC == null)
{
// This creates a live copy of the MDC
m_data.MDC = MDC.GetMap();
}
return(m_data.MDC[key] as string);
}