Concurrent uploads completely broken since V2 api.

Good idea. I modified the inner loop to this:

for i in range(10000):
    with tempfile.NamedTemporaryFile() as fp:
        metadata, restdata = client.files_download(FILE)
        fp.write(restdata.content)
        fp.write("{}\r".format(i))

        fp.seek(0)

        print '=================================='
        httplib.HTTPConnection.debuglevel = 1
        md2 = client.files_upload(fp, FILE, dropbox.files.WriteMode('overwrite', None))
        httplib.HTTPConnection.debuglevel = 0
        assert md2.size

Output:

==================================
send: 'POST /2/files/upload HTTP/1.1\r\nHost: content.dropboxapi.com\r\nConnection: keep-alive\r\nAccept-Encoding: gzip, deflate\r\nAccept: */*\r\nUser-Agent: OfficialDropboxPythonSDKv2/6.8.0\r\nContent-Type: application/octet-stream\r\nDropbox-API-Arg: {"path": "/foo/test.txt", "mode": {".tag": "overwrite"}, "autorename": false, "mute": false}\r\nAuthorization: Bearer CENSORED\r\nContent-Length: 38\r\n\r\n'
send: <open file '<fdopen>', mode 'w+b' at 0x0000000003A57390>
sendIng a read()able
reply: 'HTTP/1.1 200 OK\r\n'
header: Server: nginx
header: Date: Tue, 20 Sep 2016 17:28:13 GMT
header: Content-Type: application/json
header: Transfer-Encoding: chunked
header: Connection: keep-alive
header: pragma: no-cache
header: cache-control: no-cache
header: X-Server-Response-Time: 1122
header: X-Dropbox-Request-Id: 754c6605f013cd1dcad17ad97551c672
header: X-Robots-Tag: noindex, nofollow, noimageindex
header: Content-Encoding: gzip
==================================
send: 'POST /2/files/upload HTTP/1.1\r\nHost: content.dropboxapi.com\r\nConnection: keep-alive\r\nAccept-Encoding: gzip, deflate\r\nAccept: */*\r\nUser-Agent: OfficialDropboxPythonSDKv2/6.8.0\r\nContent-Type: application/octet-stream\r\nDropbox-API-Arg: {"path": "/foo/test.txt", "mode": {".tag": "overwrite"}, "autorename": false, "mute": false}\r\nAuthorization: Bearer CENSORED\r\nContent-Length: 41\r\n\r\n'
send: <open file '<fdopen>', mode 'w+b' at 0x0000000003771E40>
sendIng a read()able
reply: 'HTTP/1.1 200 OK\r\n'
header: Server: nginx
header: Date: Tue, 20 Sep 2016 17:28:14 GMT
header: Content-Type: application/json
header: Transfer-Encoding: chunked
header: Connection: keep-alive
header: pragma: no-cache
header: cache-control: no-cache
header: X-Server-Response-Time: 837
header: X-Dropbox-Request-Id: d716609d9fdfd3cb17001967b6f82009
header: X-Robots-Tag: noindex, nofollow, noimageindex
header: Content-Encoding: gzip
==================================
send: 'POST /2/files/upload HTTP/1.1\r\nHost: content.dropboxapi.com\r\nConnection: keep-alive\r\nAccept-Encoding: gzip, deflate\r\nAccept: */*\r\nUser-Agent: OfficialDropboxPythonSDKv2/6.8.0\r\nContent-Type: application/octet-stream\r\nDropbox-API-Arg: {"path": "/foo/test.txt", "mode": {".tag": "overwrite"}, "autorename": false, "mute": false}\r\nAuthorization: Bearer CENSORED\r\nContent-Length: 44\r\n\r\n'
send: <open file '<fdopen>', mode 'w+b' at 0x0000000003A57390>
sendIng a read()able
reply: 'HTTP/1.1 429 too_many_write_operations/..\r\n'
header: Server: nginx
header: Date: Tue, 20 Sep 2016 17:28:16 GMT
header: Content-Type: application/json
header: Transfer-Encoding: chunked
header: Connection: keep-alive
header: Retry-After: 1
header: X-Dropbox-Request-Id: 99633340ed675344e6a7d07bad3ddb4b
header: X-Robots-Tag: noindex, nofollow, noimageindex
send: 'POST /2/files/upload HTTP/1.1\r\nHost: content.dropboxapi.com\r\nConnection: keep-alive\r\nAccept-Encoding: gzip, deflate\r\nAccept: */*\r\nUser-Agent: OfficialDropboxPythonSDKv2/6.8.0\r\nContent-Type: application/octet-stream\r\nDropbox-API-Arg: {"path": "/foo/test.txt", "mode": {".tag": "overwrite"}, "autorename": false, "mute": false}\r\nAuthorization: Bearer CENSORED\r\nTransfer-Encoding: chunked\r\n\r\n'
send: '0\r\n\r\n'
reply: 'HTTP/1.1 200 OK\r\n'
header: Server: nginx
header: Date: Tue, 20 Sep 2016 17:28:18 GMT
header: Content-Type: application/json
header: Transfer-Encoding: chunked
header: Connection: keep-alive
header: pragma: no-cache
header: cache-control: no-cache
header: X-Server-Response-Time: 598
header: X-Dropbox-Request-Id: 71ff38bee72b24a9afd7172830e85671
header: X-Robots-Tag: noindex, nofollow, noimageindex
header: Content-Encoding: gzip
Traceback (most recent call last):
  File "C:/Users/Stefan/git/dropbox_test.py", line 28, in <module>
    assert md2.size
AssertionError

Seems that the upload fails for some reason (reply: 'HTTP/1.1 429 too_many_write_operations/..\r\n') and when it retries, it sends an "0\r\n\r\n" instead of "<open file '<fdopen>', mode 'w+b' at 0x0000000003A57390>" ?