@Override
    public ColorBuffer append(CharSequence csq, int start, int end) {
        try {
            buffer.append(csq, start, end);
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
        return this;
    }
Create a new ColorBuffer that stores all output to an internal buffer and only writes to the given
{@link CliPrinter} when {@link #close()} is called.

@param colors ColorFormatter used to provide colors and style.
@param sink   Where to write.
@return       Returns the created buffer.
smithy-cli/src/main/java/software/amazon/smithy/cli/ColorBuffer.java