When connecting to a named instance, a SQL client (at least SQL Server
Native Client) will send a request (namely a CLNT_UCAST_INST message) to
the server's SQL Server Browser service for instance connection
information. If it gets no response, the connection attempt fails.
By adding a SQL Server Browser responder for these requests, we ensure
that connections are successfully made to the SQL Server responder for
hash capture.
As per the comment, this is based on the document "[MC-SQLR]: SQL Server
Resolution Protocol", currently available at
<https://msdn.microsoft.com/en-us/library/cc219703.aspx>.