XPCOM Stream Guide
(xxx nsiunicharinputstream interface) (xxx nsiunicharlineinputstream interface) (xxx nsisearchableinputstream interface) stream converters (tbd: @mozilla.org/streamconverters;1) forcing an input stream to be read suppose you already have an input stream, and something to read from that input stream...but the reader doesn't do anything with the stream.

nsIConverterInputStream
1.0 66 introduced gecko 1.8 inherits from: nsiunicharinputstream last changed in gecko 1.8 (firefox 1.5 / thunderbird 1.5 / seamonkey 1.0) implemented by: @mozilla.org/intl/converter-input-stream;1.