NewTransport creates a new transport which will apply modifiers to the request on a RoundTrip call.
ReadSeekCloser combines io.ReadSeeker with io.Closer.
NewHTTPReadSeeker handles reading from an HTTP endpoint using a GET request. When seeking and starting a read from a non-zero offset the a "Range" header will be added which sets the offset. TODO(dmcgowan): Move this into a separate utility package
RequestModifier represents an object which will do an inplace modification of an HTTP request.
NewHeaderRequestModifier returns a new RequestModifier which will add the given headers to a request.