Added a clarificatory remark and one example to openReplicaSet'

Some new users might be put off by the lack of a array of choice between connection methods
that this package offers. This remark and the associated examples are a first attempt to make the package easier to start with.
--

Database/MongoDB/Connection.hs

@@ -172,6 +172,14 @@ openReplicaSetSRV hostname = do
 
 openReplicaSetSRV' :: HostName -> IO ReplicaSet 
 -- ^ Open /secure/ connections (on demand) to servers in a replica set. The seedlist and replica set name is fetched from the SRV and TXT DNS records for the given hostname. The value of 'globalConnectTimeout' at the time of this call is the timeout used for future member connect attempts. To use your own value call 'openReplicaSetSRV'''' instead.
+--
+-- The preferred connection method for cloud MongoDB providers. A typical connecting sequence is shown in the example below.
+--
+-- ==== __Example__
+-- >   do
+-- >   pipe <- openReplicatSetSRV' "cluster#.xxxxx.yyyyy.zzz"
+-- >   is_auth <- access pipe master "admin" $ auth user_name password
+-- >   unless (not is_auth) (throwIO $ userError "Authentication failed!")
 openReplicaSetSRV' hostname = do 
     timeoutSecs <- readIORef globalConnectTimeout
     _openReplicaSetSRV timeoutSecs Secure hostname

Database/MongoDB/Internal/Protocol.hs

@@ -195,7 +195,8 @@ pcall p@Pipeline{..} message = do
 -- * Pipe
 
 type Pipe = Pipeline
--- ^ Thread-safe TCP connection with pipelined requests
+-- ^ Thread-safe TCP connection with pipelined requests. In long-running applications the user is expected to use it as a "client": create a `Pipe` 
+-- at startup, use it as long as possible, and close it on shutdown. Bearing in mind that disconnections may be triggered by MongoDB service providers, the user is responsible for re-creating their `Pipe` whenever necessary. 
 
 newPipe :: ServerData -> Handle -> IO Pipe
 -- ^ Create pipe over handle

stack.yaml

@@ -0,0 +1,69 @@
+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver:
+  url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/18/21.yaml
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+#   subdirs:
+#   - auto-update
+#   - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver.
+# These entries can reference officially published versions as well as
+# forks / in-progress versions pinned to a git hash. For example:
+#
+# extra-deps:
+# - acme-missiles-0.3
+# - git: https://github.com/commercialhaskell/stack.git
+#   commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#
+# extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+flags:
+  mongoDB:
+    _old-network: false
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=2.7"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor

stack.yaml.lock

@@ -0,0 +1,13 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages: []
+snapshots:
+- completed:
+    size: 586110
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/18/21.yaml
+    sha256: ce4fb8d44f3c6c6032060a02e0ebb1bd29937c9a70101c1517b92a87d9515160
+  original:
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/18/21.yaml