Save and load SRAM at all the right times

Cargo.lock

@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
 name = "ab_glyph"
@@ -2200,6 +2200,12 @@ version = "1.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1261fe7e33c73b354eab43b1273a57c8f967d0391e80353e51f764ac02cf6775"
 
+[[package]]
+name = "oneshot"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e296cf87e61c9cfc1a61c3c63a0f7f286ed4554e0e22be84e8a38e1d264a2a29"
+
 [[package]]
 name = "orbclient"
 version = "0.3.48"
@@ -2684,6 +2690,7 @@ dependencies = [
  "itertools",
  "num-derive",
  "num-traits",
+ "oneshot",
  "pollster 0.4.0",
  "rfd",
  "rtrb",