Bail when trying to nest stream sessions using the same relay URL

Cargo.lock

@@ -99,6 +99,7 @@ dependencies = [
  "scraper",
  "serde",
  "serde_json",
+ "sha2",
  "signal-hook",
  "tempfile",
  "termion",
@@ -1627,16 +1628,17 @@ dependencies = [
 
 [[package]]
 name = "ring"
-version = "0.17.7"
+version = "0.17.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "688c63d65483050968b2a8937f7995f443e27041a0f7700aa59b0822aedebb74"
+checksum = "c17fa4cb658e3583423e915b9f3acc01cceaee1860e33d59ebae66adc3a2dc0d"
 dependencies = [
  "cc",
+ "cfg-if",
  "getrandom 0.2.12",
  "libc",
  "spin",
  "untrusted",
- "windows-sys 0.48.0",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]