Initial oss-fuzz integration. (#529)

Signed-off-by: davkor <david@adalogics.com>

fuzz/fuzz_targets/fuzz_client.rs

@@ -0,0 +1,31 @@
+#![no_main]
+use h2_support::prelude::*;
+use libfuzzer_sys::{arbitrary::Arbitrary, fuzz_target};
+
+#[derive(Debug, Arbitrary)]
+struct HttpSpec {
+    uri: Vec<u8>,
+    header_name: Vec<u8>,
+    header_value: Vec<u8>,
+}
+
+async fn fuzz_entry(inp: HttpSpec) {
+    if let Ok(req) = Request::builder()
+        .uri(&inp.uri[..])
+        .header(&inp.header_name[..], &inp.header_value[..])
+        .body(())
+    {
+        let (io, mut _srv) = mock::new();
+        let (mut client, _h2) = client::Builder::new()
+            .handshake::<_, Bytes>(io)
+            .await
+            .unwrap();
+
+        let (_, _) = client.send_request(req, true).unwrap();
+    }
+}
+
+fuzz_target!(|inp: HttpSpec| {
+    let rt = tokio::runtime::Runtime::new().unwrap();
+    rt.block_on(fuzz_entry(inp));
+});