Streaming encoder interface that makes it possible to encode a portion of a CharSequence and append it directly to the EncodedAppender instance. This solution makes it possible to just check if the input is ok and only replace the characters in the input that have to be escaped.
Encode and append portion of source CharSequence to the appender.
source- The source CharSequence
offset- Offset from which to start encoding characters
len- Number of characters to encode
appender- the appender to write to
encodingState- the current encoding state