Appends the specified character sequence to this writer.
An invocation of this method of the form out.append(csq)
behaves in exactly the same way as the invocation
out.write(csq.toString())
Depending on the specification of toString for the
character sequence csq, the entire sequence may not be
appended. For instance, invoking the toString method of a
character buffer will return a subsequence whose content depends upon
the buffer's position and limit.
Diagram: Writer