diff --git a/Cargo.toml b/Cargo.toml
index 2af3a41..5fd879a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,5 +7,8 @@ repository = "https://github.com/dermesser/integer-encoding-rs"
 documentation = "https://docs.rs/integer-encoding/"
 license-file = "LICENSE"
 keywords = ["integer", "varint", "zigzag", "protobuf", "serialize"]
+edition = "2018"
 
 [dependencies]
+async-trait = "0.1"
+futures = "0.3"
diff --git a/src/fixed.rs b/src/fixed.rs
index aa23040..380a9ad 100644
--- a/src/fixed.rs
+++ b/src/fixed.rs
@@ -7,9 +7,9 @@ pub trait FixedInt: Sized + Copy {
     /// Returns how many bytes are required to represent the given type.
     fn required_space() -> usize;
     /// Encode a value into the given slice. `dst` must be exactly `REQUIRED_SPACE` bytes.
-    fn encode_fixed(self, &mut [u8]);
+    fn encode_fixed(self, src: &mut [u8]);
     /// Decode a value from the given slice. `src` must be exactly `REQUIRED_SPACE` bytes.
-    fn decode_fixed(&[u8]) -> Self;
+    fn decode_fixed(src: &[u8]) -> Self;
     /// Perform a transmute, i.e. return a "view" into the integer's memory, which is faster than
     /// performing a copy.
     fn encode_fixed_light<'a>(&'a self) -> &'a [u8];
diff --git a/src/fixed_tests.rs b/src/fixed_tests.rs
index 92ec7d0..4176d9b 100644
--- a/src/fixed_tests.rs
+++ b/src/fixed_tests.rs
@@ -1,9 +1,9 @@
 #[cfg(test)]
 mod tests {
-    use fixed::FixedInt;
+    use crate::fixed::FixedInt;
 
-    use reader::FixedIntReader;
-    use writer::FixedIntWriter;
+    use crate::reader::FixedIntReader;
+    use crate::writer::FixedIntWriter;
 
     #[test]
     fn test_u32_enc() {
diff --git a/src/varint.rs b/src/varint.rs
index 9df391b..de295ed 100644
--- a/src/varint.rs
+++ b/src/varint.rs
@@ -30,10 +30,10 @@ pub trait VarInt: Sized + Copy {
     fn required_space(self) -> usize;
     /// Decode a value from the slice. Returns the value and the number of bytes read from the
     /// slice (can be used to read several consecutive values from a big slice)
-    fn decode_var(&[u8]) -> (Self, usize);
+    fn decode_var(src: &[u8]) -> (Self, usize);
     /// Encode a value into the slice. The slice must be at least `required_space()` bytes long.
     /// The number of bytes taken by the encoded integer is returned.
-    fn encode_var(self, &mut [u8]) -> usize;
+    fn encode_var(self, src: &mut [u8]) -> usize;
 
     /// Helper: (bit useless) - Decode value from the Vec.
     fn decode_var_vec(v: &Vec<u8>) -> (Self, usize) {
diff --git a/src/varint_tests.rs b/src/varint_tests.rs
index ce0f696..3d9438d 100644
--- a/src/varint_tests.rs
+++ b/src/varint_tests.rs
@@ -1,8 +1,8 @@
 #[cfg(test)]
 mod tests {
-    use reader::VarIntReader;
-    use varint::VarInt;
-    use writer::VarIntWriter;
+    use crate::reader::VarIntReader;
+    use crate::varint::VarInt;
+    use crate::writer::VarIntWriter;
 
     #[test]
     fn test_required_space() {
diff --git a/src/writer.rs b/src/writer.rs
index 7657efd..2a0b895 100644
--- a/src/writer.rs
+++ b/src/writer.rs
@@ -1,7 +1,7 @@
 use std::io::{Result, Write};
 
-use fixed::FixedInt;
-use varint::VarInt;
+use crate::fixed::FixedInt;
+use crate::varint::VarInt;
 
 /// A trait for writing integers in VarInt encoding to any `Write` type.
 pub trait VarIntWriter {