The latency impact of starting and stopping execution traces has been dramatically reduced.
      Execution traces may now begin or end during the garbage collection mark phase.
    </p>
    <p>
      To allow Go developers to take advantage of these improvements, an experimental
      trace reading package is available at <a href="/pkg/golang.org/x/exp/trace">golang.org/x/exp/trace</a>.

compiler may disallow the NUL character (U+0000) in the source text.
</p>
<p>
Implementation restriction: For compatibility with other tools, a
compiler may ignore a UTF-8-encoded byte order mark
(U+FEFF) if it is the first Unicode code point in the source text.
A byte order mark may be disallowed anywhere else in the source.
</p>

<h3 id="Characters">Characters</h3>

<p>
The following terms are used to denote specific Unicode character classes:

</p>
<p>
Implementation restriction: For compatibility with other tools, a
compiler may ignore a UTF-8-encoded byte order mark
(U+FEFF) if it is the first Unicode code point in the source text.
A byte order mark may be disallowed anywhere else in the source.
</p>

<h3 id="Characters">Characters</h3>

<p>