&nbsp;<span class="keyword">val</span>&nbsp;next&nbsp;:&nbsp;<span class="keywordsign">'</span>a&nbsp;<span class="constructor">Stream</span>.t&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">'</span>a<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;empty&nbsp;:&nbsp;<span class="keywordsign">'</span>a&nbsp;<span class="constructor">Stream</span>.t&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;unit<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;peek&nbsp;:&nbsp;<sp