Make client.Context implement gRPC ClientConn (#6342)

* Add QueryConn to client.Context

* Add integration test

* imports

* spelling

* Make client.Context implement grpc ClientConn

Co-authored-by: Alexander Bezobchuk <alexanderbez@users.noreply.github.com>
Co-authored-by: Federico Kunze <31522760+fedekunze@users.noreply.github.com>

client/grpc_query.go

@@ -0,0 +1,33 @@
+package client
+
+import (
+	gocontext "context"
+	"fmt"
+
+	gogogrpc "github.com/gogo/protobuf/grpc"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/grpc/encoding/proto"
+)
+
+var _ gogogrpc.ClientConn = Context{}
+
+var protoCodec = encoding.GetCodec(proto.Name)
+
+// Invoke implements the grpc ClientConn.Invoke method
+func (ctx Context) Invoke(_ gocontext.Context, method string, args, reply interface{}, _ ...grpc.CallOption) error {
+	reqBz, err := protoCodec.Marshal(args)
+	if err != nil {
+		return err
+	}
+	resBz, _, err := ctx.QueryWithData(method, reqBz)
+	if err != nil {
+		return err
+	}
+	return protoCodec.Unmarshal(resBz, reply)
+}
+
+// NewStream implements the grpc ClientConn.NewStream method
+func (Context) NewStream(gocontext.Context, *grpc.StreamDesc, string, ...grpc.CallOption) (grpc.ClientStream, error) {
+	return nil, fmt.Errorf("streaming rpc not supported")
+}