[CALCITE-2544] Replace golang.org/x/net/context with stdlib context
diff --git a/Gopkg.lock b/Gopkg.lock
index cbca26e..f54cafa 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -11,11 +11,11 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:354978aad16c56c27f57e5b152224806d87902e4935da3b03e18263d82ae77aa"
+  digest = "1:12ed7dcca9531e58c65cdadb8af0052724bef7fa1581380523fb9cb1215faf0d"
   name = "github.com/hashicorp/go-uuid"
   packages = ["."]
   pruneopts = "UT"
-  revision = "27454136f0364f2d44b1276c552d69105cf8c498"
+  revision = "de160f5c59f693fed329e73e291bb751fe4ea4dc"
 
 [[projects]]
   branch = "master"
@@ -45,18 +45,7 @@
     "pbkdf2",
   ]
   pruneopts = "UT"
-  revision = "614d502a4dac94afa3a6ce146bd1736da82514c6"
-
-[[projects]]
-  branch = "master"
-  digest = "1:d6b719875cf8091fbab38527d81d34e71f4521b9ee9ccfbd4a32cff2ac5af96e"
-  name = "golang.org/x/net"
-  packages = [
-    "context",
-    "context/ctxhttp",
-  ]
-  pruneopts = "UT"
-  revision = "8a410e7b638dca158bf9e766925842f6651ff828"
+  revision = "0709b304e793a5edb4a2c0145f281ecdc20838a4"
 
 [[projects]]
   digest = "1:c902038ee2d6f964d3b9f2c718126571410c5d81251cbab9fe58abd37803513c"
@@ -129,8 +118,6 @@
     "github.com/golang/protobuf/proto",
     "github.com/hashicorp/go-uuid",
     "github.com/xinsnake/go-http-digest-auth-client",
-    "golang.org/x/net/context",
-    "golang.org/x/net/context/ctxhttp",
     "gopkg.in/jcmturner/gokrb5.v5/client",
     "gopkg.in/jcmturner/gokrb5.v5/config",
     "gopkg.in/jcmturner/gokrb5.v5/credentials",
diff --git a/Gopkg.toml b/Gopkg.toml
index f0ae2ae..39ebede 100644
--- a/Gopkg.toml
+++ b/Gopkg.toml
@@ -34,10 +34,6 @@
   version = "0.4.0"
 
 [[constraint]]
-  branch = "master"
-  name = "golang.org/x/net"
-
-[[constraint]]
   name = "gopkg.in/jcmturner/gokrb5.v5"
   version = "5.3.0"
 
diff --git a/connection.go b/connection.go
index 760e393..3cc9c04 100644
--- a/connection.go
+++ b/connection.go
@@ -18,11 +18,11 @@
 package avatica
 
 import (
+	"context"
 	"database/sql/driver"
 
 	"github.com/apache/calcite-avatica-go/v3/errors"
 	"github.com/apache/calcite-avatica-go/v3/message"
-	"golang.org/x/net/context"
 )
 
 type conn struct {
diff --git a/driver.go b/driver.go
index 5f4d8e1..a9d60fb 100644
--- a/driver.go
+++ b/driver.go
@@ -32,6 +32,7 @@
 package avatica
 
 import (
+	"context"
 	"database/sql"
 	"database/sql/driver"
 	"fmt"
@@ -41,7 +42,6 @@
 	"github.com/apache/calcite-avatica-go/v3/message"
 	"github.com/apache/calcite-avatica-go/v3/phoenix"
 	"github.com/hashicorp/go-uuid"
-	"golang.org/x/net/context"
 )
 
 // Driver is exported to allow it to be used directly.
diff --git a/go.mod b/go.mod
index dae17bf..e90b0c7 100644
--- a/go.mod
+++ b/go.mod
@@ -9,7 +9,7 @@
 	github.com/stretchr/testify v1.2.2 // indirect
 	github.com/xinsnake/go-http-digest-auth-client v0.4.0
 	golang.org/x/crypto v0.0.0-20180820150726-614d502a4dac // indirect
-	golang.org/x/net v0.0.0-20180826012351-8a410e7b638d
+	golang.org/x/net v0.0.0-20180826012351-8a410e7b638d // indirect
 	golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f // indirect
 	gopkg.in/jcmturner/aescts.v1 v1.0.1 // indirect
 	gopkg.in/jcmturner/dnsutils.v1 v1.0.1 // indirect
diff --git a/go.sum b/go.sum
index 1c32e52..77aa97d 100644
--- a/go.sum
+++ b/go.sum
@@ -14,8 +14,9 @@
 github.com/xinsnake/go-http-digest-auth-client v0.4.0/go.mod h1:QK1t1v7ylyGb363vGWu+6Irh7gyFj+N7+UZzM0L6g8I=
 golang.org/x/crypto v0.0.0-20180820150726-614d502a4dac h1:7d7lG9fHOLdL6jZPtnV4LpI41SbohIJ1Atq7U991dMg=
 golang.org/x/crypto v0.0.0-20180820150726-614d502a4dac/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
-golang.org/x/net v0.0.0-20180826012351-8a410e7b638d h1:g9qWBGx4puODJTMVyoPrpoxPFgVGd+z1DZwjfRu4d0I=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20180906233101-161cd47e91fd h1:nTDtHvHSdCn1m6ITfMRqtOd/9+7a3s8RBNOZ3eYZzJA=
+golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f h1:wMNYb4v58l5UBM7MYRLPG6ZhfOqbKu7X5eyFl8ZhKvA=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 gopkg.in/jcmturner/aescts.v1 v1.0.1 h1:cVVZBK2b1zY26haWB4vbBiZrfFQnfbTVrE3xZq6hrEw=
diff --git a/http_client.go b/http_client.go
index cdd05c5..823a33f 100644
--- a/http_client.go
+++ b/http_client.go
@@ -19,6 +19,7 @@
 
 import (
 	"bytes"
+	"context"
 	"database/sql/driver"
 	"fmt"
 	"io/ioutil"
@@ -31,8 +32,6 @@
 	avaticaMessage "github.com/apache/calcite-avatica-go/v3/message"
 	"github.com/golang/protobuf/proto"
 	"github.com/xinsnake/go-http-digest-auth-client"
-	"golang.org/x/net/context"
-	"golang.org/x/net/context/ctxhttp"
 	"gopkg.in/jcmturner/gokrb5.v5/client"
 	"gopkg.in/jcmturner/gokrb5.v5/config"
 	"gopkg.in/jcmturner/gokrb5.v5/credentials"
@@ -180,7 +179,9 @@
 		c.kerberosClient.SetSPNEGOHeader(req, "")
 	}
 
-	res, err := ctxhttp.Do(ctx, c.httpClient, req)
+	req = req.WithContext(ctx)
+
+	res, err := c.httpClient.Do(req)
 
 	if err != nil {
 		return nil, err
diff --git a/rows.go b/rows.go
index 9e8187d..fa3eddb 100644
--- a/rows.go
+++ b/rows.go
@@ -18,13 +18,13 @@
 package avatica
 
 import (
+	"context"
 	"database/sql/driver"
 	"io"
 	"time"
 
 	"github.com/apache/calcite-avatica-go/v3/internal"
 	"github.com/apache/calcite-avatica-go/v3/message"
-	"golang.org/x/net/context"
 )
 
 type resultSet struct {
diff --git a/statement.go b/statement.go
index 6ec30c6..3e3cab2 100644
--- a/statement.go
+++ b/statement.go
@@ -18,13 +18,13 @@
 package avatica
 
 import (
+	"context"
 	"database/sql/driver"
 	"errors"
 	"math"
 	"time"
 
 	"github.com/apache/calcite-avatica-go/v3/message"
-	"golang.org/x/net/context"
 )
 
 type stmt struct {
diff --git a/transaction.go b/transaction.go
index 53bc76e..826068f 100644
--- a/transaction.go
+++ b/transaction.go
@@ -18,8 +18,9 @@
 package avatica
 
 import (
+	"context"
+
 	"github.com/apache/calcite-avatica-go/v3/message"
-	"golang.org/x/net/context"
 )
 
 type tx struct {