An entity that can be sent or received with an HTTP message.
Entities can be found in some
HttpEntityEnclosingRequest requests and in
HttpResponse responses , where they are optional.
In some places, the JavaDoc distinguishes three kinds of entities,
depending on where their
HttpEntity.getContent content originates:
streamed: The content is received from a stream, or
generated on the fly.
Represents a protocol version, as specified in RFC 2616.
RFC 2616 specifies only HTTP versions, like "HTTP/1.1" and "HTTP/1.0".
RFC 3261 specifies a message format that is identical to HTTP except
for the protocol name.