rpc/client: take context as first param (#5347)

Closes #5145

also applies to light/client

rpc/client/examples_test.go

@@ -2,6 +2,7 @@ package client_test
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"log"
 
@@ -31,7 +32,7 @@ func ExampleHTTP_simple() {
 
 	// Broadcast the transaction and wait for it to commit (rather use
 	// c.BroadcastTxSync though in production).
-	bres, err := c.BroadcastTxCommit(tx)
+	bres, err := c.BroadcastTxCommit(context.Background(), tx)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -40,7 +41,7 @@ func ExampleHTTP_simple() {
 	}
 
 	// Now try to fetch the value for the key
-	qres, err := c.ABCIQuery("/key", k)
+	qres, err := c.ABCIQuery(context.Background(), "/key", k)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -95,26 +96,26 @@ func ExampleHTTP_batching() {
 	for _, tx := range txs {
 		// Broadcast the transaction and wait for it to commit (rather use
 		// c.BroadcastTxSync though in production).
-		if _, err := batch.BroadcastTxCommit(tx); err != nil {
+		if _, err := batch.BroadcastTxCommit(context.Background(), tx); err != nil {
 			log.Fatal(err)
 		}
 	}
 
 	// Send the batch of 2 transactions
-	if _, err := batch.Send(); err != nil {
+	if _, err := batch.Send(context.Background()); err != nil {
 		log.Fatal(err)
 	}
 
 	// Now let's query for the original results as a batch
 	keys := [][]byte{k1, k2}
 	for _, key := range keys {
-		if _, err := batch.ABCIQuery("/key", key); err != nil {
+		if _, err := batch.ABCIQuery(context.Background(), "/key", key); err != nil {
 			log.Fatal(err)
 		}
 	}
 
 	// Send the 2 queries and keep the results
-	results, err := batch.Send()
+	results, err := batch.Send(context.Background())
 	if err != nil {
 		log.Fatal(err)
 	}