message: introduce s3 feature in cargo toml
diff: @@ -56,15 +56,17 @@ async-trait = "0.1.40"
  xaynet-macros = { path = "../xaynet-macros", version = "0.1.0" }
  xaynet-core = { path = "../xaynet-core", version = "0.1.0" }
  redis = { version = "0.17.0", default-features = false, features = ["connection-manager", "aio", "tokio-rt-core", "script"] }
  -rusoto_core = "0.45.0"
  -rusoto_s3 = "0.45.0"
  -hex = "0.4.2"
  -fancy-regex = "0.4.0"
  num_enum = "0.5.1"
  # optional dependencies
  +# metrics feature
  influxdb = { version = "0.1.0", features = ["derive"], optional = true }
  chrono = { version = "0.4.15", optional = true }
  +# model-persistence feature
  +rusoto_core = { version = "0.45.0", optional = true }
  +rusoto_s3 = { version = "0.45.0", optional = true }
  +hex = { version = "0.4.2", optional = true }
  +fancy-regex = { version = "0.4.0", optional = true }
  [dev-dependencies]
  tower-test = "0.3.0"
  @@ -82,6 +84,7 @@ path = "src/bin/main.rs"
  [features]
  default = []
  -full = ["tls", "metrics"]
  tls = ["warp/tls"]
  metrics = ["influxdb", "chrono"]
  +model-persistence = ["rusoto_core", "rusoto_s3", "hex", "fancy-regex"]
  +full = ["tls", "metrics", "model-persistence"]
  