+#
+# fields:
+# httpd: PublicInbox::HTTPD ref
+# env: PSGI env hashref
+# input_left: bytes left to read in request body (e.g. POST/PUT)
+# remote_addr: remote IP address as a string (e.g. "127.0.0.1")
+# remote_port: peer port
+# forward: response body object, response to ->getline + ->close
+# alive: HTTP keepalive state:
+# 0: drop connection when done
+# 1: keep connection when done
+# 2: keep connection, chunk responses