ContentRangeheader
ContentRangeHeader, formally the Content-Range HTTP header, is used by a server to describe a partial delivery of a resource. It is sent in responses that fulfill a Range request or in multipart responses that deliver subranges of a resource. The header is most commonly associated with byte-range requests and the 206 Partial Content status code, signaling that only a portion of the resource is being transferred.
The syntax of the header is Content-Range: unit start-end/size. The unit is typically bytes. A common form
The meaning of the values is straightforward: start and end specify the inclusive byte positions of the
Content-Range is complementary to the Range request header. The client sends Range headers to request specific