Impl new func SessionBuilder::compression

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

Author: NobodyXu

src/builder.rs

@@ -49,6 +49,7 @@ pub struct SessionBuilder {
     known_hosts_check: KnownHosts,
     control_dir: Option<PathBuf>,
     config_file: Option<PathBuf>,
+    compression: Option<bool>,
 }
 
 impl Default for SessionBuilder {
@@ -62,6 +63,7 @@ impl Default for SessionBuilder {
             known_hosts_check: KnownHosts::Add,
             control_dir: None,
             config_file: None,
+            compression: None,
         }
     }
 }
@@ -137,6 +139,23 @@ impl SessionBuilder {
         self
     }
 
+    /// Enable or disable compression (including stdin, stdout, stderr, data
+    /// for forwarded TCP and unix-domain connections, sftp and scp
+    /// connections).
+    ///
+    /// NOTE that the ssh server can forcibly disable the compression.
+    ///
+    /// By default, ssh uses configure value set in `~/.ssh/config`.
+    ///
+    /// If `~/.ssh/config` does not enable compression, then it is disabled
+    /// by default.
+    ///
+    /// Defaults to `None`.
+    pub fn compression(&mut self, compression: bool) -> &mut Self {
+        self.compression = Some(compression);
+        self
+    }
+
     /// Connect to the host at the given `host` over SSH using process impl, which will
     /// spawn a new ssh process for each `Child` created.
     ///
@@ -277,6 +296,12 @@ impl SessionBuilder {
             init.arg("-F").arg(config_file);
         }
 
+        if let Some(compression) = self.compression {
+            let arg = if compression { "yes" } else { "no" };
+
+            init.arg("-o").arg(format!("Compression={}", arg));
+        }
+
         init.arg(destination);
 
         // we spawn and immediately wait, because the process is supposed to fork.