snippet.swift

let begin = request.hasByteRaange ? request.byteRange.lowerBound : 0
let end = request.hasByteRaange ? request.byteRange.higherBound : clipFileSize
var readHead = begin
let response = GCDWebServerStreamedResponse(contentType: "video/mp4", asyncStreamBlock: { block in
  if readHead < end {
     let data = getData(readHead, chunkSize)
     block(data, nil)
     readHead += data.count
  } else {
     block(nil, nil)    
  }
})