Try #127:

ct.sh

@@ -13,6 +13,7 @@ if [ $TRAVIS_RUST_VERSION = "stable" ] || [ $TRAVIS_RUST_VERSION = "beta" ] || [
     rustup default $TRAVIS_RUST_VERSION
     # make sure that explicitly providing the default target works
     cargo test --target x86_64-unknown-linux-gnu
+    cargo test --release
     cargo test --features spin_threading
     cargo test --features rust_threading
     cargo test --features custom_time,custom_gmtime_r

mbedtls/Cargo.toml

@@ -30,6 +30,7 @@ num-bigint = { version = "0.2", optional = true }
 bit-vec = { version = "0.5", optional = true }
 block-modes = { version = "0.3", optional = true }
 rc2 = { version = "0.3", optional = true }
+tokio = { version = "0.3", optional = true }
 
 [target.x86_64-fortanix-unknown-sgx.dependencies]
 rs-libc = "0.1.0"
@@ -83,6 +84,16 @@ name = "server"
 path = "examples/server.rs"
 required-features = ["std"]
 
+[[test]]
+name = "alpn"
+path = "tests/alpn.rs"
+required-features = ["std"]
+
+[[test]]
+name = "async_session"
+path = "tests/async_session.rs"
+required-features = ["std", "threading", "tokio", "tokio/net", "tokio/io-util", "tokio/macros"]
+
 [[test]]
 name = "client_server"
 path = "tests/client_server.rs"

mbedtls/src/rng/ctr_drbg.rs

@@ -102,6 +102,9 @@ impl<'entropy> DerefMut for CtrDrbg<'entropy> {
 
 // ==== END IMMOVABLE TYPE KLUDGE ====
 
+#[cfg(feature = "threading")]
+unsafe impl<'entropy> Send for CtrDrbg<'entropy> {}
+
 #[cfg(feature = "threading")]
 unsafe impl<'entropy> Sync for CtrDrbg<'entropy> {}