title: C# XmlWriter namespace issues
body: <p>I'm using <code>XmlWriter</code> and I'm struggling to create the following XML tag.</p>
  
  <pre><code>&lt;mzML xmlns="http://psi.hupo.org/ms/mzml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://psi.hupo.org/ms/mzml http://psidev.info/files/ms/mzML/xsd/mzML1.1.0_idx.xsd" version="1.1"&gt;
  </code></pre>
  
  <p>I have the following:</p>
  
  <pre><code>XmlWriterSettings settings = new XmlWriterSettings();
  settings.Indent = true;
  
  XmlWriter xmlWriter = XmlWriter.Create(xmlFilePath, settings);
  
  xmlWriter.WriteStartDocument();
  
  xmlWriter.WriteStartElement("mzML", "xmlns", @"http://psi.hupo.org/ms/mzml");
  
  xmlWriter.WriteAttributeString("xsi", "xmlns", @"http://www.w3.org/2001/XMLSchema-instance");
  
  xmlWriter.WriteAttributeString("schemaLocation", "xsi", @"http://psi.hupo.org/ms/mzml http://psidev.info/files/ms/mzML/xsd/mzML1.1.0.xsd");
  
  xmlWriter.WriteAttributeString("version", "1.1");
  
  xmlWriter.WriteEndElement();
  
  xmlWriter.WriteEndDocument();
  
  xmlWriter.Close();
  </code></pre>
  
  <p>which results in the following:</p>
  
  <pre><code>&lt;mzML:xmlns p1:xsi="http://www.w3.org/2001/XMLSchema-instance" p2:schemaLocation="http://psi.hupo.org/ms/mzml http://psidev.info/files/ms/mzML/xsd/mzML1.1.0.xsd" version="1.1.0" xmlns:p2="xsi" xmlns:p1="xmlns" xmlns:mzML="http://psi.hupo.org/ms/mzml"&gt;
  </code></pre>
  
  <p>The documentation is confusing me; I've tried lots of variations of the above code but can't seem to get anywhere close to my target XML tag.  </p>
  
  <p>Can anybody please help?</p>
  
  <p>(P.S. I need to use <code>XmlWriter</code> due to the size of the XML files I need to create.)</p>