There are several use-cases which require the usage of a custom ILcdOWSTransport. For example:

Configuring the custom transport on the model decoder

When you want to visualize WMS data on a map, you first use the WMS model decoder to create an ILcdModel, as illustrated in Visualize WMS data on a Lightspeed map tutorial.

You can pass the custom transport to the constructor of the model decoder, and the model decoder will use this transport: 

TLcdOGCWMSProxyModelDecoder modelDecoder =
    new TLcdOGCWMSProxyModelDecoder(customTransport, null);

Configuring the custom transport on the TLcdWMSClient

When you want to send your own WMS requests to the server, you use the TLcdWMSClient directly. Creating a client which uses a custom transport is done by passing the transport to the factory method: 

TLcdWMSClient client = TLcdWMSClient.createWMSClient(serverURI, customTransport, null);