diff --git a/Cargo.toml b/Cargo.toml
index d6978deb8b50cbaffd0d11dd124dccbef5758d6e..e555a0d97ebe3d1cb46ebae6cdf79c9fd3a41ca2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -43,7 +43,7 @@ crate-type = [
 ]
 
 [features]
-default = ["ffi", "session_optimization"]
+default = ["ffi"]
 ffi = [] # see src/ffi/mod.rs
 ffi_pseudo_socket_api = ["ffi", "libc", "os_socketaddr"]# see src/ffi/pseudo_socket_api.rs.
 endpoint_logging = [] # see src/macros.rs
diff --git a/examples/bench_27/main.c b/examples/bench_27/main.c
new file mode 100644
index 0000000000000000000000000000000000000000..8471d124fc401559b6fef1281c42e21292a2ca7e
--- /dev/null
+++ b/examples/bench_27/main.c
@@ -0,0 +1,57 @@
+#include <time.h>
+#include "../../reowolf.h"
+#include "../utility.c"
+int main(int argc, char** argv) {
+    int i, rounds;
+    char optimized = argv[1][0];
+    rounds = atoi(argv[2]);
+    printf("optimized %c, rounds %d\n", optimized, rounds);
+
+    unsigned char pdl[] = "\
+    primitive xrouter(in a, out b, out c) {\
+        while(true) synchronous {\
+            if(fires(a)) {\
+                if(fires(b)) put(b, get(a));\
+                else         put(c, get(a));\
+            }\
+        }\
+    }\
+    ";
+    Arc_ProtocolDescription * pd = protocol_description_parse(pdl, sizeof(pdl)-1);
+    printf("Error str `%s`\n", reowolf_error_peek(NULL));
+    Connector * c = connector_new_with_id(pd, 0);
+    PortId ports[8];
+    if(optimized=='y') {
+        connector_add_port_pair(c, &ports[0], &ports[1]);
+        connector_add_port_pair(c, &ports[2], &ports[7]); // 3,4,5,6 uninitialized
+        connector_add_component(c, "sync", 4, ports+1, 2);
+        printf("Error str `%s`\n", reowolf_error_peek(NULL));
+    } else {
+        for(i=0; i<4; i++) {
+            connector_add_port_pair(c, &ports[i*2+0], &ports[i*2+1]);
+        }
+        connector_add_component(c, "xrouter", 7, (PortId[]) {ports[1],ports[2],ports[4]}, 3);
+        printf("Error str `%s`\n", reowolf_error_peek(NULL));
+        connector_add_component(c, "merger" , 6, (PortId[]) {ports[3],ports[5],ports[6]}, 3);
+        printf("Error str `%s`\n", reowolf_error_peek(NULL));
+    }
+    connector_connect(c, -1);
+    printf("Error str `%s`\n", reowolf_error_peek(NULL));
+
+    size_t msg_len = 1000;
+    char * msg = malloc(msg_len);
+    memset(msg, 42, msg_len);
+    
+    clock_t begin = clock();
+    for (i=0; i<rounds; i++) {
+        connector_put_bytes(c, ports[0], msg, msg_len);
+        connector_get(c, ports[7]);
+        connector_sync(c, -1);
+    }
+    clock_t end = clock();
+    double time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
+    printf("Time Spent: %f\n", time_spent);
+
+    free(msg);
+    return 0;
+}
\ No newline at end of file
diff --git a/examples/bench_28/main.c b/examples/bench_28/main.c
new file mode 100644
index 0000000000000000000000000000000000000000..1c913a3bdf5e207f55ce0f07a83c83b7160e1774
--- /dev/null
+++ b/examples/bench_28/main.c
@@ -0,0 +1,43 @@
+#include <time.h>
+#include "../../reowolf.h"
+#include "../utility.c"
+int main(int argc, char** argv) {
+    int i, rounds;
+    char optimized = argv[1][0];
+    rounds = atoi(argv[2]);
+    printf("optimized %c, rounds %d\n", optimized, rounds);
+
+    unsigned char pdl[] = "";
+    Arc_ProtocolDescription * pd = protocol_description_parse(pdl, sizeof(pdl)-1);
+    printf("Error str `%s`\n", reowolf_error_peek(NULL));
+    Connector * c = connector_new_with_id(pd, 0);
+    PortId ports[6];
+    for(i=0; i<3; i++) {
+        connector_add_port_pair(c, &ports[i*2+0], &ports[i*2+1]);
+    }
+    connector_add_component(c, "sync", 4, ports+1, 2);
+    if(optimized=='y') {
+        connector_add_component(c, "forward", 7, ports+3, 2);
+    } else {
+        connector_add_component(c, "sync",    4, ports+3, 2);
+    }
+    connector_connect(c, -1);
+    printf("Error str `%s`\n", reowolf_error_peek(NULL));
+
+    size_t msg_len = 1000;
+    char * msg = malloc(msg_len);
+    memset(msg, 42, msg_len);
+    
+    clock_t begin = clock();
+    for (i=0; i<rounds; i++) {
+        connector_put_bytes(c, ports[0], msg, msg_len);
+        connector_get(c, ports[5]);
+        connector_sync(c, -1);
+    }
+    clock_t end = clock();
+    double time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
+    printf("Time Spent: %f\n", time_spent);
+
+    free(msg);
+    return 0;
+}
\ No newline at end of file
diff --git a/examples/bench_29/main.c b/examples/bench_29/main.c
new file mode 100644
index 0000000000000000000000000000000000000000..09ca280740f9d97ea5e696dee8825dabd2d0fde9
--- /dev/null
+++ b/examples/bench_29/main.c
@@ -0,0 +1,92 @@
+#include <time.h>
+#include "../../reowolf.h"
+#include "../utility.c"
+FfiSocketAddr addr_new(const uint8_t ipv4[4], uint16_t port) {
+    FfiSocketAddr x;
+    x.port = port;
+    memcpy(x.ipv4, ipv4, sizeof(uint8_t)*4);
+    return x;
+}
+int main(int argc, char** argv) {
+    int i, rounds;
+    char optimized = argv[1][0];
+    char sender = argv[2][0];
+    rounds = atoi(argv[3]);
+    uint8_t ipv4[4] = { atoi(argv[4]), atoi(argv[5]), atoi(argv[6]), atoi(argv[7]) };
+    size_t msg_len = atoi(argv[8]);
+
+    printf("optimized %c, sender %c, rounds %d, addr %d.%d.%d.%d, msg_len %d\n",
+        optimized, sender, rounds, ipv4[0], ipv4[1], ipv4[2], ipv4[3], msg_len);
+
+    unsigned char pdl[] = "\
+    primitive filter(in i, out o) {\
+        while(true) synchronous() {\
+            msg m = get(i);\
+            if(m[0] == 0) put(o, m);\
+        }\
+    }\
+    ";
+    Arc_ProtocolDescription * pd = protocol_description_parse(pdl, sizeof(pdl)-1);
+    printf("Error str `%s`\n", reowolf_error_peek(NULL));
+    Connector * c = connector_new_with_id(pd, sender=='y'?1:0);
+    PortId ports[3]; // orientation: 0->1->2 (subsets may be initialized) sender puts on 0. !sender gets on 2. 
+    char ident[] = "filter";
+    FfiSocketAddr addr = addr_new(ipv4, 7000);
+    if(sender=='y') {
+        Polarity p = Polarity_Putter;
+        EndpointPolarity ep = EndpointPolarity_Active;
+        if(optimized=='y') {
+            // 3 ports: (native)0-->1(filter)2-->(NETWORK)
+            connector_add_port_pair(c, &ports[0], &ports[1]);
+            connector_add_net_port(c, &ports[2], addr, p, ep);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+            connector_add_component(c, ident, sizeof(ident)-1, ports+1, 2);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+        } else {
+            // 1 port
+            connector_add_net_port(c, &ports[0], addr, p, ep);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+        }
+    } else {
+        Polarity p = Polarity_Getter;
+        EndpointPolarity ep = EndpointPolarity_Passive;
+        if(optimized=='y') {
+            // 1 port
+            connector_add_net_port(c, &ports[2], addr, p, ep);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+        } else {
+            // 3 ports: (NETWORK)-->0(filter)1-->2(native)
+            connector_add_net_port(c, &ports[0], addr, p, ep);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+            connector_add_port_pair(c, &ports[1], &ports[2]);
+            connector_add_component(c, ident, sizeof(ident)-1, ports, 2);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+        }
+    }
+    connector_connect(c, -1);
+    printf("Error str `%s`\n", reowolf_error_peek(NULL));
+
+    char * msg = malloc(msg_len);
+    memset(msg, 42, msg_len);
+    
+    clock_t begin = clock();
+    for (i=0; i<rounds; i++) {
+        if(sender=='y') {
+            msg[0] = (char) i%2;
+            connector_put_bytes(c, ports[0], msg, msg_len);
+            // always put
+        } else {
+            // no-get option
+            connector_next_batch(c);
+            // get option
+            connector_get(c, ports[2]);
+        }
+        connector_sync(c, -1);
+    }
+    clock_t end = clock();
+    double time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
+    printf("Time Spent: %f\n", time_spent);
+
+    free(msg);
+    return 0;
+}
\ No newline at end of file
diff --git a/examples/bench_30/main.c b/examples/bench_30/main.c
new file mode 100644
index 0000000000000000000000000000000000000000..2689459d4655d7c6100b103c2412b30fc3cc75dc
--- /dev/null
+++ b/examples/bench_30/main.c
@@ -0,0 +1,93 @@
+#include <time.h>
+#include "../../reowolf.h"
+#include "../utility.c"
+FfiSocketAddr addr_new(const uint8_t ipv4[4], uint16_t port) {
+    FfiSocketAddr x;
+    x.port = port;
+    memcpy(x.ipv4, ipv4, sizeof(uint8_t)*4);
+    return x;
+}
+int main(int argc, char** argv) {
+    int i, rounds;
+    char optimized = argv[1][0];
+    char sender = argv[2][0];
+    rounds = atoi(argv[3]);
+    uint8_t ipv4[4] = { atoi(argv[4]), atoi(argv[5]), atoi(argv[6]), atoi(argv[7]) };
+    size_t msg_len = atoi(argv[8]);
+
+    printf("optimized %c, sender %c, rounds %d, addr %d.%d.%d.%d, msg_len %d\n",
+        optimized, sender, rounds, ipv4[0], ipv4[1], ipv4[2], ipv4[3], msg_len);
+
+    unsigned char pdl[] = "";
+    Arc_ProtocolDescription * pd = protocol_description_parse(pdl, sizeof(pdl)-1);
+    printf("Error str `%s`\n", reowolf_error_peek(NULL));
+    Connector * c = connector_new_with_id(pd, sender=='y'?1:0);
+
+    PortId ports[5]; // sender always puts 0, receiver always gets 3, 4
+    char ident[] = "replicator";
+    FfiSocketAddr addrs[2] = {
+        addr_new(ipv4, 7000),
+        addr_new(ipv4, 7001)
+    };
+    if(sender=='y') {
+        Polarity p = Polarity_Putter;
+        EndpointPolarity ep = EndpointPolarity_Active;
+        if(optimized=='y') {
+            // 1 port: (native)0-->(NETWORK)
+            connector_add_net_port(c, &ports[0], addrs[0], p, ep);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+        } else {
+            // 4 ports: (native)0-->1(replicator)2-->(NETWORK)
+            //                                   3-->(NETWORK)
+            connector_add_port_pair(c, &ports[0], &ports[1]);
+            connector_add_net_port(c, &ports[2], addrs[0], p, ep);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+            connector_add_net_port(c, &ports[3], addrs[1], p, ep);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+            connector_add_component(c, ident, sizeof(ident)-1, ports+1, 3);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+        }
+    } else {
+        Polarity p = Polarity_Getter;
+        EndpointPolarity ep = EndpointPolarity_Passive;
+        if(optimized=='y') {
+            // 5 ports: (NETWORK)-->0(replicator)1-->3(native)
+            //                                   2-->4
+            connector_add_net_port(c, &ports[0], addrs[0], p, ep);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+            connector_add_port_pair(c, &ports[1], &ports[3]);
+            connector_add_port_pair(c, &ports[2], &ports[4]);
+            connector_add_component(c, ident, sizeof(ident)-1, ports, 3);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+        } else {
+            // 2 ports: (NETWORK)-->3(native)
+            //                   -->4
+            connector_add_net_port(c, &ports[3], addrs[0], p, ep);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+            connector_add_net_port(c, &ports[4], addrs[1], p, ep);
+            printf("Error str `%s`\n", reowolf_error_peek(NULL));
+        }
+    }
+    connector_connect(c, -1);
+    printf("Error str `%s`\n", reowolf_error_peek(NULL));
+
+    char * msg = malloc(msg_len);
+    memset(msg, 42, msg_len);
+    
+    clock_t begin = clock();
+    for (i=0; i<rounds; i++) {
+        if(sender=='y') {
+            connector_put_bytes(c, ports[0], msg, msg_len);
+        } else {
+            connector_get(c, ports[3]);
+            connector_get(c, ports[4]);
+        }
+        connector_sync(c, -1);
+    }
+    clock_t end = clock();
+    double time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
+    printf("Time Spent: %f\n", time_spent);
+
+    free(msg);
+    return 0;
+}
\ No newline at end of file
diff --git a/src/protocol/inputsource.rs b/src/protocol/inputsource.rs
index cbf32808cb2a174ec42bf310295cf70cbc598ab7..d32a32a8d4fdfced36e7620ce21089d1cdedaa98 100644
--- a/src/protocol/inputsource.rs
+++ b/src/protocol/inputsource.rs
@@ -28,10 +28,12 @@ primitive alternator(in i, out l, out r) {
     }
 }
 primitive replicator(in i, out l, out r) {
-    while(true) synchronous() if(fires(i)) {
-        msg m = get(i);
-        put(l, m);
-        put(r, m);
+    while(true) synchronous {
+        if(fires(i)) {
+            msg m = get(i);
+            put(l, m);
+            put(r, m);
+        }
     }
 }
 primitive merger(in l, in r, out o) {
diff --git a/src/runtime/setup.rs b/src/runtime/setup.rs
index dfc7f5fff1c3cb78eb2e71b5bc163f1502b13941..756b35163da295fc139fa0538673d3c4b0c0e608 100644
--- a/src/runtime/setup.rs
+++ b/src/runtime/setup.rs
@@ -250,6 +250,9 @@ impl Connector {
     ) -> Result<Self, (ConnectError, Box<dyn Logger>)> {
         log!(cu.logger, "~~~ CONNECT called timeout {:?}", timeout);
         let deadline = timeout.map(|to| Instant::now() + to);
+        // `try_complete` is a helper function, which DOES NOT own `cu`, and returns ConnectError on err.
+        // This outer function takes its output and wraps it alongside `cu` (which it owns)
+        // as appropriate for Err(...) and OK(...) cases.
         let mut try_complete = || {
             // connect all endpoints in parallel; send and receive peer ids through ports
             let mut endpoint_manager = setup_endpoints_and_pair_ports(
@@ -1030,12 +1033,12 @@ fn session_optimize(
 // and returning an optimized map.
 fn leader_session_map_optimize(
     logger: &mut dyn Logger,
-    unoptimized_map: HashMap<ConnectorId, SessionInfo>,
+    mut m: HashMap<ConnectorId, SessionInfo>,
 ) -> Result<HashMap<ConnectorId, SessionInfo>, ConnectError> {
     log!(logger, "Session map optimize START");
     // currently, it's the identity function
     log!(logger, "Session map optimize END");
-    Ok(unoptimized_map)
+    Ok(m)
 }
 
 // Modify the given connector's internals to reflect
@@ -1052,7 +1055,7 @@ fn apply_my_optimizations(
         endpoint_incoming_to_getter,
     } = session_info;
     // simply overwrite the contents
-    // println!("BEFORE: {:#?}\n{:#?}", cu, comm);
+    println!("BEFORE: {:#?}\n{:#?}", cu, comm);
     cu.ips.port_info = port_info;
     assert!(cu.ips.port_info.invariant_preserved());
     cu.proto_components = proto_components;
diff --git a/src/runtime/tests.rs b/src/runtime/tests.rs
index 9e558be20b3d78599677f97bc3cd877c37dd1fa1..0a650114e5bc24e126c26fbc2b717ad25c50e09d 100644
--- a/src/runtime/tests.rs
+++ b/src/runtime/tests.rs
@@ -1309,30 +1309,3 @@ fn for_msg_byte() {
     }
     c.sync(None).unwrap();
 }
-
-#[test]
-fn message_concat() {
-    // Note: PDL quirks:
-    // 1. declarations as first lines of a scope
-    // 2. var names cannot be prefixed by types. Eg `msg_concat` prohibited.
-    let test_log_path = Path::new("./logs/message_concat");
-    let pdl = b"
-    primitive message_concat(out o) {
-        msg a = create(1);
-        msg b = create(1);
-        a[0] = 0;
-        b[0] = 1;
-        synchronous() put(o, a+b);
-    }
-    ";
-    let pd = reowolf::ProtocolDescription::parse(pdl).unwrap();
-    let mut c = file_logged_configured_connector(0, test_log_path, Arc::new(pd));
-
-    // setup a session between (a) native, and (b) sequencer3, connected by 3 ports.
-    let [p0, g0] = c.new_port_pair();
-    c.add_component(b"message_concat", &[p0]).unwrap();
-    c.connect(None).unwrap();
-    c.get(g0).unwrap();
-    c.sync(None).unwrap();
-    assert_eq!(&[0, 1], c.gotten(g0).unwrap().as_slice());
-}