Add dependency on futures

I need it to handle the `wgpu` API.

Cargo.lock

@@ -279,6 +279,7 @@ checksum = "00b0228411908ca8685dba7fc2cdd70ec9990a6e753e89b6ac91a84c40fbaf4b"
 name = "fornjot"
 version = "0.1.0"
 dependencies = [
+ "futures",
  "wgpu",
  "winit",
 ]
@@ -299,6 +300,101 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
 
+[[package]]
+name = "futures"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e05b85ec287aac0dc34db7d4a569323df697f9c55b99b15d6b4ef8cde49f613"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-executor",
+ "futures-io",
+ "futures-sink",
+ "futures-task",
+ "futures-util",
+]
+
+[[package]]
+name = "futures-channel"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f366ad74c28cca6ba456d95e6422883cfb4b252a83bed929c83abfdbbf2967d5"
+dependencies = [
+ "futures-core",
+ "futures-sink",
+]
+
+[[package]]
+name = "futures-core"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "59f5fff90fd5d971f936ad674802482ba441b6f09ba5e15fd8b39145582ca399"
+
+[[package]]
+name = "futures-executor"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "10d6bb888be1153d3abeb9006b11b02cf5e9b209fda28693c31ae1e4e012e314"
+dependencies = [
+ "futures-core",
+ "futures-task",
+ "futures-util",
+]
+
+[[package]]
+name = "futures-io"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "de27142b013a8e869c14957e6d2edeef89e97c289e69d042ee3a49acd8b51789"
+
+[[package]]
+name = "futures-macro"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d0b5a30a4328ab5473878237c447333c093297bded83a4983d10f4deea240d39"
+dependencies = [
+ "proc-macro-hack",
+ "proc-macro2 1.0.19",
+ "quote 1.0.7",
+ "syn",
+]
+
+[[package]]
+name = "futures-sink"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f2032893cb734c7a05d85ce0cc8b8c4075278e93b24b66f9de99d6eb0fa8acc"
+
+[[package]]
+name = "futures-task"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bdb66b5f09e22019b1ab0830f7785bcea8e7a42148683f99214f73f8ec21a626"
+dependencies = [
+ "once_cell",
+]
+
+[[package]]
+name = "futures-util"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8764574ff08b701a084482c3c7031349104b07ac897393010494beaa18ce32c6"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-io",
+ "futures-macro",
+ "futures-sink",
+ "futures-task",
+ "memchr",
+ "pin-project",
+ "pin-utils",
+ "proc-macro-hack",
+ "proc-macro-nested",
+ "slab",
+]
+
 [[package]]
 name = "fxhash"
 version = "0.2.1"
@@ -566,6 +662,12 @@ version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "60302e4db3a61da70c0cb7991976248362f30319e88850c487b9b95bbf059e00"
 
+[[package]]
+name = "memchr"
+version = "2.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3728d817d99e5ac407411fa471ff9800a778d88a24685968b36824eaf4bee400"
+
 [[package]]
 name = "memmap"
 version = "0.7.0"
@@ -753,6 +855,12 @@ dependencies = [
  "cc",
 ]
 
+[[package]]
+name = "once_cell"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b631f7e854af39a1739f401cf34a8a013dfe09eac4fa4dba91e9768bd28168d"
+
 [[package]]
 name = "ordered-float"
 version = "1.1.0"
@@ -814,6 +922,32 @@ version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d4fd5641d01c8f18a23da7b6fe29298ff4b55afcccdf78973b24cf3175fee32e"
 
+[[package]]
+name = "pin-project"
+version = "0.4.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca4433fff2ae79342e497d9f8ee990d174071408f28f726d6d83af93e58e48aa"
+dependencies = [
+ "pin-project-internal",
+]
+
+[[package]]
+name = "pin-project-internal"
+version = "0.4.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c0e815c3ee9a031fdf5af21c10aa17c573c9c6a566328d99e3936c34e36461f"
+dependencies = [
+ "proc-macro2 1.0.19",
+ "quote 1.0.7",
+ "syn",
+]
+
+[[package]]
+name = "pin-utils"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
+
 [[package]]
 name = "pkg-config"
 version = "0.3.18"
@@ -829,6 +963,18 @@ dependencies = [
  "toml",
 ]
 
+[[package]]
+name = "proc-macro-hack"
+version = "0.5.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "99c605b9a0adc77b7211c6b1f722dcb613d68d66859a44f3d485a6da332b0598"
+
+[[package]]
+name = "proc-macro-nested"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eba180dafb9038b050a4c280019bbedf9f2467b61e5d892dcad585bb57aadc5a"
+
 [[package]]
 name = "proc-macro2"
 version = "0.4.30"

Cargo.toml

@@ -5,5 +5,6 @@ authors = ["Hanno Braun <hb@hannobraun.de>"]
 edition = "2018"
 
 [dependencies]
+futures = "*"
 wgpu    = "*"
 winit   = "*"