nsIStreamConverter Interface

 nsIStreamConverter provides an interface to implement when you have code
 that converts data from one type to another.

 Suppose you had code that converted plain text into HTML. You could implement
 this interface to allow everyone else to use your conversion logic using a 
 standard api.
 <p>
 <b>STREAM CONVERTER USERS</b>

 There are currently two ways to use a stream converter:
 <ol>
 <li> <b>SYNCHRONOUS</b> Stream to Stream
    You can supply the service with a stream of type X
    and it will convert it to your desired output type and return
    a converted (blocking) stream to you.</li>

 <li> <b>ASYNCHRONOUS</b> nsIStreamListener to nsIStreamListener
    You can supply data directly to the converter by calling it's
    nsIStreamListener::OnDataAvailable() method. It will then
    convert that data from type X to your desired output type and
    return converted data to you via the nsIStreamListener you passed
    in by calling its OnDataAvailable() method.</li>
 </ol>
 <p>

 <b>STREAM CONVERTER SUPPLIERS</b>

 Registering a stream converter:
 Stream converter registration is a two step process. First of all the stream
 converter implementation must register itself with the component manager using
 a contractid in the format below. Second, the stream converter must add the contractid
 to the registry.

 Stream converter contractid format (the stream converter root key is defined in this
 file):

 <pre>@mozilla.org/streamconv;1?from=FROM_MIME_TYPE&to=TO_MIME_TYPE</pre>

 @author Jud Valeski
 @see nsIStreamConverterService