drop tcp mid-chunk and force browser to re-hs before it can be retried

ok with subchunks as of writing; 6thr, u2sz=1
303M file: --s-wr-slp 0.02 --iobuf 131072
33.5M file: --s-wr-slp 0.1 --iobuf 131072

--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -234,2 +234,3 @@ ZIP_XCODE_L = _build_zip_xcode()
 ZIP_XCODE_S = set(ZIP_XCODE_L)
+hcblk = ""
 
@@ -3154,2 +3155,3 @@ class HttpCli(object):
     def handle_post_json(self) -> bool:
+        global hcblk
         try:
@@ -3248,2 +3250,3 @@ class HttpCli(object):
         # not to protect u2fh, but to prevent handshakes while files are closing
+        hcblk = ""
         with self.u2mutex:
@@ -3335,2 +3338,3 @@ class HttpCli(object):
     def handle_post_binary(self) -> bool:
+        global hcblk
         try:
@@ -3452,2 +3456,4 @@ class HttpCli(object):
                     )
+                    if chash == hcblk:
+                        raise Exception("fhdsafhad re")
                     post_sz, _, sha_b64 = hashcopy(
@@ -3513,3 +3519,6 @@ class HttpCli(object):
                         self.u2fh.put(path, f)
-            except:
+            except Exception as ex:
+                if "fhdsafhad" in str(ex):
+                    hcblk = chashes[0]
+                    self.sr.s.close()
                 # maybe busted handle (eg. disk went full)
--- a/copyparty/util.py
+++ b/copyparty/util.py
@@ -3414,2 +3414,3 @@ def eol_conv(
 
+hcn = 0
 def hashcopy(
@@ -3421,2 +3422,4 @@ def hashcopy(
 ) -> tuple[int, str, str]:
+    global hcn
+    print(hcn)
     if not hashobj:
@@ -3429,2 +3432,5 @@ def hashcopy(
 
+        hcn += 1
+        if hcn in (24, 121, 300, 600, 900):
+            raise Exception("fhdsafhad " + str(tlen))
         hashobj.update(buf)