fix clippy

Signed-off-by: Jay Lee <BusyJayLee@gmail.com>
diff --git a/src/channel.rs b/src/channel.rs
index 61c77ce..7f15d9b 100644
--- a/src/channel.rs
+++ b/src/channel.rs
@@ -182,7 +182,7 @@
 
     /// Set whether to allow the use of `SO_REUSEPORT` if available. Defaults to `true`.
     pub fn reuse_port(mut self, reuse: bool) -> ChannelBuilder {
-        let opt = if reuse { 1 } else { 0 };
+        let opt = reuse as i32;
         self.options.insert(
             Cow::Borrowed(grpcio_sys::GRPC_ARG_ALLOW_REUSEPORT),
             Options::Integer(opt),
@@ -588,7 +588,7 @@
     // If try_to_connect is true, the channel will try to establish a connection, potentially
     // changing the state.
     fn check_connectivity_state(&self, try_to_connect: bool) -> ConnectivityState {
-        let should_try = if try_to_connect { 1 } else { 0 };
+        let should_try = try_to_connect as i32;
         unsafe { grpc_sys::grpc_channel_check_connectivity_state(self.channel, should_try) }
     }
 }
diff --git a/src/security/credentials.rs b/src/security/credentials.rs
index 78c54cd..0654355 100644
--- a/src/security/credentials.rs
+++ b/src/security/credentials.rs
@@ -102,7 +102,7 @@
         panic!("fetcher user_data must be set up!");
     }
     let f: &mut dyn ServerCredentialsFetcher =
-        (&mut *(user_data as *mut Box<dyn ServerCredentialsFetcher>)).as_mut();
+        (*(user_data as *mut Box<dyn ServerCredentialsFetcher>)).as_mut();
     let result = f.fetch();
     match result {
         Ok(Some(builder)) => {
diff --git a/src/task/promise.rs b/src/task/promise.rs
index e9b3646..cc2d21a 100644
--- a/src/task/promise.rs
+++ b/src/task/promise.rs
@@ -9,7 +9,7 @@
 use crate::metadata::UnownedMetadata;
 
 /// Batch job type.
-#[derive(PartialEq, Debug)]
+#[derive(PartialEq, Eq, Debug)]
 pub enum BatchType {
     /// Finish without reading any message.
     Finish,