The ContentType property returns content type for the
current resource. Changing this value sets the content type for
the next request submitted to the server.
This property returns a value based on the Content-Type response
header and does not examine the contents of the payload returned by
the server. If the web server does not recognize the data format of
the resource it is returning, this property should return a value of
application/octet-stream. However, some servers incorrectly
return unrecognized formats as text/plain, causing the payload
to be identified as human-readable text rather than binary data.
Some servers will return a content type of text/plain for
JSON responses and others will use the IANA standard type of
application/json. If the server returns an XML payload, it may
indicate the content type either as text/xml or
application/xml.