How to print a document's content to the debug output?

I see that in the XSL there is an instruction that prints some text to the debug output console.

<xsl:message>
    SOME MESSAGES
</xsl:message>

How can I print the whole document's content to开发者_开发技巧 the console?

---

Try

<xsl:message>
  <xsl:copy-of select="/"/>
</xsl:message>

or simply

<xsl:message select="/"/>

Which XSLT 2.0 procesor do you use?