feat(upload): Add transfer_speed for downloading and uploading files (#1797)

Co-authored-by: Victor Aremu <me@victorare.mu>
Co-authored-by: Fabian-Lars <github@fabianlars.de>

plugins/upload/src/transfer_stats.rs

@@ -0,0 +1,52 @@
+// Copyright 2019-2023 Tauri Programme within The Commons Conservancy
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-License-Identifier: MIT
+
+use std::time::Instant;
+
+// The TransferStats struct is used to track and calculate the transfer speed of data chunks over time.
+pub struct TransferStats {
+    accumulated_chunk_len: usize, // Total length of chunks transferred in the current period
+    accumulated_time: u128,       // Total time taken for the transfers in the current period
+    pub transfer_speed: u64,      // Calculated transfer speed in bytes per second
+    start_time: Instant,          // Time when the current period started
+    granularity: u32, // Time period (in milliseconds) over which the transfer speed is calculated
+}
+
+impl TransferStats {
+    // Initializes a new TransferStats instance with the specified granularity.
+    pub fn start(granularity: u32) -> Self {
+        Self {
+            accumulated_chunk_len: 0,
+            accumulated_time: 0,
+            transfer_speed: 0,
+            start_time: Instant::now(),
+            granularity,
+        }
+    }
+    // Records the transfer of a data chunk and updates the transfer speed if the granularity period has elapsed.
+    pub fn record_chunk_transfer(&mut self, chunk_len: usize) {
+        let now = Instant::now();
+        let it_took = now.duration_since(self.start_time).as_millis();
+        self.accumulated_chunk_len += chunk_len;
+        self.accumulated_time += it_took;
+
+        // If the accumulated time exceeds the granularity, calculate the transfer speed.
+        if self.accumulated_time >= self.granularity as u128 {
+            self.transfer_speed =
+                (self.accumulated_chunk_len as u128 / self.accumulated_time * 1024) as u64;
+            self.accumulated_chunk_len = 0;
+            self.accumulated_time = 0;
+        }
+
+        // Reset the start time for the next period.
+        self.start_time = now;
+    }
+}
+
+// Provides a default implementation for TransferStats with a granularity of 500 milliseconds.
+impl Default for TransferStats {
+    fn default() -> Self {
+        Self::start(500) // Default granularity is 500
+    }
+}