response outroduction

// ContentType sets the response writer's
// header "Content-Type" to the 'cType'.
ContentType(cType string)
// GetContentType returns the response writer's
// header value of "Content-Type".
GetContentType() string
// GetContentType returns the request's
// trim-ed(without the charset and priority values)
// header value of "Content-Type".
GetContentTypeRequested() string

// GetContentLength returns the request's
// header value of "Content-Length".
GetContentLength() int64

Write(body []byte) (int, error)
// Writef formats according to a format specifier and writes to the response.
Writef(format string, args ...interface{}) (int, error)
// WriteString writes a simple string to the response.
WriteString(body string) (int, error)
// WriteNotModified sends a 304 "Not Modified" status code to the client,
// it makes sure that the content type, the content length headers
// and any "ETag" are removed before the response sent.
WriteNotModified()
// WriteWithExpiration works like `Write` but it will
// check if a resource is modified,
// based on the "modtime" input argument,
// otherwise sends a 304 status code in order to
// leave the client-side render the cached content.
WriteWithExpiration(body []byte, modtime time.Time) (int, error)