docs(examples): point cluster-sensitive RPC examples at mainnet-beta

Several examples queried testnet, where the underlying data is sparse
or economically meaningless (few validators voting, no real inflation
rewards paid out, low-balance largest accounts). Point them at mainnet-
beta so they return representative data:

- getBlockProduction: drop the redundant second call and switch to
  mainnet-beta.
- getInflationGovernor / getInflationRate / getLargestAccounts: endpoint
  swap only.
- getInflationReward: fetch a currently-voting validator via
  GetVoteAccounts instead of hardcoding a testnet pubkey, so the example
  keeps producing rewards across epochs.
- getVoteAccounts: drop the stale testnet VotePubkey filter, list all
  vote accounts, and print a summary (mainnet has >1000).

Author: sonicfromnewyoke

rpc/examples/getBlockProduction/getBlockProduction.go

@@ -22,30 +22,19 @@ import (
 )
 
 func main() {
-	endpoint := rpc.TestNet_RPC
-	client := rpc.New(endpoint)
+	ctx := context.Background()
+	// Testnet has few validators; mainnet-beta has the real schedule.
+	client := rpc.New(rpc.MainNetBeta_RPC)
 
-	{
-		out, err := client.GetBlockProduction(context.TODO())
-		if err != nil {
-			panic(err)
-		}
-		spew.Dump(out)
-	}
-	{
-		out, err := client.GetBlockProductionWithOpts(
-			context.TODO(),
-			&rpc.GetBlockProductionOpts{
-				Commitment: rpc.CommitmentFinalized,
-				// Range: &rpc.SlotRangeRequest{
-				// 	FirstSlot: XXXXXX,
-				// 	Identity:  solana.MustPublicKeyFromBase58("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"),
-				// },
-			},
-		)
-		if err != nil {
-			panic(err)
-		}
-		spew.Dump(out)
+	out, err := client.GetBlockProductionWithOpts(
+		ctx,
+		&rpc.GetBlockProductionOpts{
+			Commitment: rpc.CommitmentFinalized,
+			// Range: &rpc.SlotRangeRequest{ FirstSlot: ..., Identity: ... },
+		},
+	)
+	if err != nil {
+		panic(err)
 	}
+	spew.Dump(out)
 }

rpc/examples/getInflationGovernor/getInflationGovernor.go

@@ -22,8 +22,7 @@ import (
 )
 
 func main() {
-	endpoint := rpc.TestNet_RPC
-	client := rpc.New(endpoint)
+	client := rpc.New(rpc.MainNetBeta_RPC)
 
 	out, err := client.GetInflationGovernor(
 		context.TODO(),

rpc/examples/getInflationRate/getInflationRate.go

@@ -22,8 +22,7 @@ import (
 )
 
 func main() {
-	endpoint := rpc.TestNet_RPC
-	client := rpc.New(endpoint)
+	client := rpc.New(rpc.MainNetBeta_RPC)
 
 	out, err := client.GetInflationRate(
 		context.TODO(),

rpc/examples/getInflationReward/getInflationReward.go

@@ -23,16 +23,23 @@ import (
 )
 
 func main() {
-	endpoint := rpc.TestNet_RPC
-	client := rpc.New(endpoint)
+	ctx := context.Background()
+	client := rpc.New(rpc.MainNetBeta_RPC)
 
-	pubKey := solana.MustPublicKeyFromBase58("6dmNQ5jwLeLk5REvio1JcMshcbvkYMwy26sJ8pbkvStu")
+	// Fetch any currently-voting validator so the example keeps working
+	// across epochs without a hardcoded pubkey.
+	voteAccounts, err := client.GetVoteAccounts(ctx, nil)
+	if err != nil {
+		panic(err)
+	}
+	if len(voteAccounts.Current) == 0 {
+		panic("no current vote accounts")
+	}
+	votePubkey := voteAccounts.Current[0].VotePubkey
 
 	out, err := client.GetInflationReward(
-		context.TODO(),
-		[]solana.PublicKey{
-			pubKey,
-		},
+		ctx,
+		[]solana.PublicKey{votePubkey},
 		&rpc.GetInflationRewardOpts{
 			Commitment: rpc.CommitmentFinalized,
 		},

rpc/examples/getLargestAccounts/getLargestAccounts.go

@@ -22,8 +22,7 @@ import (
 )
 
 func main() {
-	endpoint := rpc.TestNet_RPC
-	client := rpc.New(endpoint)
+	client := rpc.New(rpc.MainNetBeta_RPC)
 
 	out, err := client.GetLargestAccounts(
 		context.TODO(),

rpc/examples/getVoteAccounts/getVoteAccounts.go

@@ -16,24 +16,30 @@ package main
 
 import (
 	"context"
+	"fmt"
 
-	"github.com/davecgh/go-spew/spew"
-	"github.com/gagliardetto/solana-go"
 	"github.com/gagliardetto/solana-go/rpc"
 )
 
 func main() {
-	endpoint := rpc.TestNet_RPC
-	client := rpc.New(endpoint)
+	ctx := context.Background()
+	client := rpc.New(rpc.MainNetBeta_RPC)
 
-	out, err := client.GetVoteAccounts(
-		context.TODO(),
-		&rpc.GetVoteAccountsOpts{
-			VotePubkey: solana.MustPublicKeyFromBase58("vot33MHDqT6nSwubGzqtc6m16ChcUywxV7tNULF19Vu").ToPointer(),
-		},
-	)
+	// Without options, returns every vote account on the cluster. To
+	// filter to one validator, pass &GetVoteAccountsOpts{VotePubkey: &...}.
+	out, err := client.GetVoteAccounts(ctx, nil)
 	if err != nil {
 		panic(err)
 	}
-	spew.Dump(out)
+
+	// Full response is large on mainnet; print a summary.
+	fmt.Println("current vote accounts:", len(out.Current))
+	fmt.Println("delinquent vote accounts:", len(out.Delinquent))
+	for i, v := range out.Current {
+		if i >= 5 {
+			break
+		}
+		fmt.Printf("  %s  stake=%d commission=%d%%\n",
+			v.VotePubkey, v.ActivatedStake, v.Commission)
+	}
 }