* Make sure config.TimeoutBroadcastTxCommit < rpcserver.WriteTimeout()

* remove redundant comment

* libs/rpc/http_server: move Read/WriteTimeout into Config

* increase defaults for read/write timeouts

Based on this article
https://www.digitalocean.com/community/tutorials/how-to-optimize-nginx-configuration

* WriteTimeout should be larger than TimeoutBroadcastTxCommit

* set a deadline for subscribing to txs

* extract duration into const

* add two changelog entries

* Update CHANGELOG_PENDING.md

Co-Authored-By: melekes <anton.kalyaev@gmail.com>

* Update CHANGELOG_PENDING.md

Co-Authored-By: melekes <anton.kalyaev@gmail.com>

* 12 -> 10

* changelog

* changelog

* limit number of /subscribe clients and queries per client

Add the following config variables (under [rpc] section):
  * max_subscription_clients
  * max_subscriptions_per_client
  * timeout_broadcast_tx_commit

Fixes #2826

new HTTPClient interface for subscriptions

finalize HTTPClient events interface

remove EventSubscriber

fix data race

```
WARNING: DATA RACE
Read at 0x00c000a36060 by goroutine 129:
  github.com/tendermint/tendermint/rpc/client.(*Local).Subscribe.func1()
      /go/src/github.com/tendermint/tendermint/rpc/client/localclient.go:168 +0x1f0

Previous write at 0x00c000a36060 by goroutine 132:
  github.com/tendermint/tendermint/rpc/client.(*Local).Subscribe()
      /go/src/github.com/tendermint/tendermint/rpc/client/localclient.go:191 +0x4e0
  github.com/tendermint/tendermint/rpc/client.WaitForOneEvent()
      /go/src/github.com/tendermint/tendermint/rpc/client/helpers.go:64 +0x178
  github.com/tendermint/tendermint/rpc/client_test.TestTxEventsSentWithBroadcastTxSync.func1()
      /go/src/github.com/tendermint/tendermint/rpc/client/event_test.go:139 +0x298
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162

Goroutine 129 (running) created at:
  github.com/tendermint/tendermint/rpc/client.(*Local).Subscribe()
      /go/src/github.com/tendermint/tendermint/rpc/client/localclient.go:164 +0x4b7
  github.com/tendermint/tendermint/rpc/client.WaitForOneEvent()
      /go/src/github.com/tendermint/tendermint/rpc/client/helpers.go:64 +0x178
  github.com/tendermint/tendermint/rpc/client_test.TestTxEventsSentWithBroadcastTxSync.func1()
      /go/src/github.com/tendermint/tendermint/rpc/client/event_test.go:139 +0x298
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162

Goroutine 132 (running) created at:
  testing.(*T).Run()
      /usr/local/go/src/testing/testing.go:878 +0x659
  github.com/tendermint/tendermint/rpc/client_test.TestTxEventsSentWithBroadcastTxSync()
      /go/src/github.com/tendermint/tendermint/rpc/client/event_test.go:119 +0x186
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:827 +0x162
==================
```

lite client works (tested manually)

godoc comments

httpclient: do not close the out channel

use TimeoutBroadcastTxCommit

no timeout for unsubscribe

but 1s Local (5s HTTP) timeout for resubscribe

format code

change Subscribe#out cap to 1

and replace config vars with RPCConfig

TimeoutBroadcastTxCommit can't be greater than rpcserver.WriteTimeout

rpc: Context as first parameter to all functions

reformat code

fixes after my own review

fixes after Ethan's review

add test stubs

fix config.toml

* fixes after manual testing

- rpc: do not recommend to use BroadcastTxCommit because it's slow and wastes
Tendermint resources (pubsub)
- rpc: better error in Subscribe and BroadcastTxCommit
- HTTPClient: do not resubscribe if err = ErrAlreadySubscribed

* fixes after Ismail's review

* Update rpc/grpc/grpc_test.go

Co-Authored-By: melekes <anton.kalyaev@gmail.com>

1."abci_query": rpcserver.NewRPCFunc(c.ABCIQuery, "path,data,prove")
"validators": rpcserver.NewRPCFunc(c.Validators, "height"),
the parameters and function do not match, cause index out of range error.
2. the prove of query is forced to be true, while default option is false.
3. fix the wrong key of merkle

* Decouple StartHTTP{,AndTLS}Server from Listen()

This should help solve cosmos/cosmos-sdk#2715

* Fix small mistake

* Update StartGRPCServer

* s/rpc/rpcserver/

* Start grpccore.StartGRPCServer in a goroutine

* Reinstate l.Close()

* Fix rpc/lib/test/main.go

* Update code comment

* update changelog and comments

* fix tm-monitor. more comments

This reverts commit d02c5d1e30.

Refs #1740

also, expose limit option for number concurrent streams for gRPC
(unlimited by default)

This reverts commit 96a3502

* Vulnerability in light client proxy

When calling GetCertifiedCommit the light client proxy would call
Certify and even on error return the Commit as if it had been correctly
certified.

Now it returns the error correctly and returns an empty Commit on error.

* Improve names for clarity

The lite package now contains StaticCertifier, DynamicCertifier and
InqueringCertifier. This also changes the method receivers from one
letter to two letter names, which will make future refactoring easier
and follows the coding standards.

* Fix test failures

* Rename files

* remove dead code