* <code>SmbFile</code> or in the case of URLs that only specify a server
     * or workgroup, the server or workgroup will be returned. The name of
     * the root URL <code>smb1://</code> is also <code>smb1://</code>. If this
     * {@code SmbFile} refers to a workgroup, server, share, or directory,
     * the name will include a trailing slash '/' so that composing new

     * Retrieve the hostname of the server for this SMB resource. If this
     * <code>SmbFile</code> references a workgroup, the name of the workgroup
     * is returned. If this <code>SmbFile</code> refers to the root of this
     * SMB network hierarchy, <code>null</code> is returned.
     *
     * @return The server or workgroup name or <code>null</code> if this
     *         <code>SmbFile</code> refers to the root <code>smb://</code> resource.