chunkedUpload.swift

...

let data = String(count: 100*1024*1024, repeatedValue: Character("A")).dataUsingEncoding(NSUTF8StringEncoding)!
let chunkSize = 5 * 1024 * 1024 // 5MB
var offset = 0
var sessionId = ""

func uploadFirstChunk() {
    let size = min(chunkSize, data.length)
    self.client.files.uploadSessionStart(body:
        data.subdataWithRange(NSMakeRange(0, size)))
        .response { response, error in
            if let result = response {
                self.sessionId = result.sessionId
                self.offset += size
                print("So far \(self.offset) bytes have been uploaded.")
                self.uploadNextChunk()
            } else {
                print("uploadSessionStart failed")
            }
        }
}

func uploadNextChunk() {
    if data.length - offset <= chunkSize {
        let size = data.length - offset
        client.files.uploadSessionFinish(
            cursor: Files.UploadSessionCursor(
                sessionId: self.sessionId, offset: UInt64(self.offset)),
            commit: Files.CommitInfo(path: "/foo"),
            body: data.subdataWithRange(NSMakeRange(self.offset, size)))
            .response { response, error in
                if error != nil {
                    print("uploadSessionFinish failed: \(error)")
                } else {
                    print("Done!")
                }
            }
    } else {
        client.files.uploadSessionAppend(
            sessionId: self.sessionId,
            offset: UInt64(self.offset),
            body: data.subdataWithRange(NSMakeRange(self.offset, chunkSize)))
            .response { response, error in
                if error != nil {
                    print("uploadSessionAppend failed: \(error)")
                } else {
                    self.offset += self.chunkSize
                    print("So far \(self.offset) bytes have been uploaded.")
                    self.uploadNextChunk()
                }
            }
    }
}