evergreen fixes

.evergreen/config.yml

@@ -608,7 +608,11 @@ functions:
       params:
         script: |
           ${PREPARE_SHELL}
+          export MONGODB_URI="${MONGODB_URI}"
           ${DRIVERS_TOOLS}/.evergreen/run-load-balancer.sh start
+    - command: expansions.update
+      params:
+        file: lb-expansion.yml
 
   "stop load balancer":
     - command: shell.exec

.evergreen/generate-uri.sh

@@ -10,13 +10,29 @@ DRIVERS_TOOLS_X509=`echo "$DRIVERS_TOOLS_X509" | sed 's/\//%2F/g'`
 CA_FILE="${DRIVERS_TOOLS_X509}%2Fca.pem"
 CERT_FILE="${DRIVERS_TOOLS_X509}%2Fclient.pem"
 
+update_uri() {
+    local ORIG_URI=$1
+    if [[ "$ORIG_URI" == "" ]]; then
+        return
+    fi
+    if [[ "$ORIG_URI" == *"?"* ]]; then
+        ORIG_URI="${ORIG_URI}&"
+    else
+        ORIG_URI="${ORIG_URI}/?"
+    fi
+    echo "${ORIG_URI}tls=true&tlsCAFile=${CA_FILE}&tlsCertificateKeyFile=${CERT_FILE}&tlsAllowInvalidCertificates=true"
+}
+
 if [[ "$MONGODB_URI" == *"?"* ]]; then
     export MONGODB_URI="${MONGODB_URI}&"
 else
     export MONGODB_URI="${MONGODB_URI}/?"
 fi
 
-
-export MONGODB_URI="${MONGODB_URI}tls=true&tlsCAFile=${CA_FILE}&tlsCertificateKeyFile=${CERT_FILE}&tlsAllowInvalidCertificates=true"
+export MONGODB_URI="$(update_uri ${MONGODB_URI})"
+export SINGLE_MONGOS_LB_URI="$(update_uri ${SINGLE_MONGOS_LB_URI})"
+export MULTI_MONGOS_LB_URI="$(update_uri ${MULTI_MONGOS_LB_URI})"
 
 echo "MONGODB_URI: ${MONGODB_URI}"
+echo "SINGLE_MONGOS_LB_URI: ${SINGLE_MONGOS_LB_URI}"
+echo "MULTI_MONGOS_LB_URI: ${MULTI_MONGOS_LB_URI}"

src/sdam/state/mod.rs

@@ -144,7 +144,7 @@ impl Topology {
                 // be selected.
                 let new_desc = ServerDescription {
                     server_type: ServerType::LoadBalancer,
-                    average_round_trip_time: Some(Duration::ZERO),
+                    average_round_trip_time: Some(Duration::from_nanos(0)),
                     ..ServerDescription::new(server_address.clone(), None)
                 };
                 topology_state