Remove unused imports and a couple unused muts

sqlx-core/src/mysql/connection.rs

@@ -121,7 +121,7 @@ impl MySqlConnection {
         // We must have a separate buffer around the stream as we can't operate directly
         // on bytes returned from the stream. We have various kinds of payload manipulation
         // that must be handled before decoding.
-        let mut payload = ret_if_none!(self.stream.peek(self.packet_len).await?);
+        let payload = ret_if_none!(self.stream.peek(self.packet_len).await?);
         self.packet.extend_from_slice(payload);
         self.stream.consume(self.packet_len);
 

sqlx-core/src/mysql/types/chrono.rs

@@ -1,6 +1,6 @@
 use std::convert::TryFrom;
 
-use byteorder::{BigEndian, ByteOrder, LittleEndian};
+use byteorder::{ByteOrder, LittleEndian};
 use chrono::{DateTime, Datelike, NaiveDate, NaiveDateTime, NaiveTime, Timelike, Utc};
 
 use crate::decode::{Decode, DecodeError};

sqlx-core/src/mysql/types/int.rs

@@ -22,7 +22,7 @@ impl Encode<MySql> for i8 {
 }
 
 impl Decode<MySql> for i8 {
-    fn decode(mut buf: &[u8]) -> Result<Self, DecodeError> {
+    fn decode(buf: &[u8]) -> Result<Self, DecodeError> {
         Ok(buf[0] as i8)
     }
 }