Add continuous mode

Author: ig11987

README.md

@@ -48,21 +48,27 @@ On the receiving end, suppose we download with 32 TCP connections:
 
 File modification timestamps are preserved during all transfers.
 
-## Incremental transfers
+## Continuous mode
 
-Fastsync supports incremental transfers with the `--incremental` flag. When enabled, fastsync will:
+Fastsync supports continuous mode with the `--continuous` flag. When enabled, fastsync will:
 
 1. Compare files by name, size, and modification timestamp
 2. Skip files that already exist at the destination with matching size and timestamp
 3. Transfer only files that are missing or have different size/timestamp
+4. Keep syncing in rounds with a 2-second delay between rounds
+5. After each transfer round, wait and then re-scan the source files
+6. If changes are detected in the new scan, start another sync round
+7. Stop when 5 consecutive rounds finish with no changes detected
 
-Both sender and receiver must use the `--incremental` flag:
+Both sender and receiver must use the `--continuous` flag:
+
+    # Receiver
+    fastsync recv <ip>:<port> 32 --continuous
 
     # Sender
-    fastsync send 100.71.154.83:4440 --incremental file.tar.gz
+    fastsync send --continuous <ip>:<port> ./data
 
-    # Receiver
-    fastsync recv 100.71.154.83:4440 32 --incremental
+**Note:** Continuous mode only handles file additions and modifications. File deletions from the sender are not propagated to the receiver - files that exist at the destination will remain even if they're removed from the source.
 
 ## Testing
 

rust-toolchain.toml

@@ -1,5 +1,5 @@
 [toolchain]
-channel = "1.74.0"
+channel = "1.75.0"
 components = ["rustc", "cargo", "rustfmt", "clippy"]
 targets = [
   # Default regular build.