ses a field or type to be kept by DCE.">@:keep</span><span class="label label-meta label-meta-directlyUsed" title="Marks types that are directly referenced by non-extern code.">@:directlyUsed</span></div><div class="body"><div class="doc doc-main"><p>A String buffer is an efficient way to build a big string by appending small
elements together.</p>
<p>Unlike String, an instance of StringBuf is not immutable in the sense that
it can be passed as argument to functions which modify it by appending more
values.