title: raw decoder for protobufs format
body: <p>I'd like to find a way to convert a binary protobuf message into a human readable description of the contained data, without using the .proto files.</p>
  
  <p>The background is that I have a .proto message that it being rejected by the parser on Android, but it's not entirely clear why. I could go through the message by hand, but it's rather tedious.</p>
  
  <p>I tried <code>protoc --decode_raw</code>, but it just gives the error "Failed to parse input.". I google hoping/expecting someone would have done a nice web utility that might do this, but haven't found anything obvious.</p>
  
  <p>I'm just hoping to get some output like:</p>
  
  <pre><code>field 1: varint: 128
  field 4: string: "foo"
  </code></pre>
  
  <p>Any pointers in the right direction would be most welcome!</p>