\showframe

\startbuffer
\setlocalhsize
\dontleavehmode\framed[width=\hsize]      {\the\hsize,\the\localhsize,\setlocalhsize\the\localhsize,\type{\hsize      }} \par
\dontleavehmode\framed[width=\localhsize] {\the\hsize,\the\localhsize,\setlocalhsize\the\localhsize,\type{\localhsize }} \par
\dontleavehmode\framed[width=\textwidth]  {\the\hsize,\the\localhsize,\setlocalhsize\the\localhsize,\type{\textwidth  }} \par
\dontleavehmode\framed[width=\makeupwidth]{\the\hsize,\the\localhsize,\setlocalhsize\the\localhsize,\type{\makeupwidth}} \par
\dontleavehmode\framed[width=local]       {\the\hsize,\the\localhsize,\setlocalhsize\the\localhsize,\type{local}}        \par
\dontleavehmode\blackrule[width=\hsize]       \par
\dontleavehmode\blackrule[width=\localhsize]  \par
\dontleavehmode\blackrule[width=\textwidth]   \par
\dontleavehmode\blackrule[width=\makeupwidth] \par
\dontleavehmode\ruledhbox to \hsize      {x\hss x} \par
\dontleavehmode\ruledhbox to \localhsize {x\hss x} \par
\dontleavehmode\ruledhbox to \textwidth  {x\hss x} \par
\dontleavehmode\ruledhbox to \makeupwidth{x\hss x} \par
\stopbuffer

\starttext

\startitemize
    \startitem
        \getbuffer
    \stopitem
\stopitemize

\getbuffer

\stoptext
