Package stream contains internal stream parsing and handling behavior.
Errors related to stream handling
Expect reads a token from d and expects that it will be a new stream start token. If not, an error is returned. It then handles feature negotiation for the new stream. If an XML header is discovered instead, it is skipped.
Reader returns a token reader that handles stream level tokens on an already established stream.
Send sends a new XML header followed by a stream start element on the given io.Writer. We don't use an xml.Encoder both because Go's standard library xml package really doesn't like the namespaced stream:stream attribute and because we can guarantee well-formedness of the XML with a print in this case and printing is much faster than encoding. Afterwards, clear the StreamRestartRequired bit and set the output stream information.