Large refactor. Use rayon, 10X performance boost

Code changes:
Removed ignore & channel crates. Using a single reciever thread to build
a hashmap to prevend duplicate inodes being reported gave a severe
performance penalty

Using rayon crate with some hand crafted file traversal has improved
performance aprox 10X

Behaviour changes:

Removed parameter 'limit by filesystem' - don't think this is used, and
I only added it as it was easy to add with the ignore crate.

Sym links will now not appear in the output tree unless using '-s'
'apparent-size' flag

Change behaviour of multiple args so that it unifies them and
compares them under one tree instead of treating them
individually: https://github.com/bootandy/dust/issues/136

Cargo.lock

@@ -29,9 +29,9 @@ dependencies = [
 
 [[package]]
 name = "assert_cmd"
-version = "1.0.4"
+version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8f57fec1ac7e4de72dcc69811795f1a7172ed06012f80a5d1ee651b62484f588"
+checksum = "a88b6bd5df287567ffdf4ddf4d33060048e1068308e5f62d81c6f9824a045a48"
 dependencies = [
  "bstr",
  "doc-comment",
@@ -52,6 +52,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "autocfg"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
+
 [[package]]
 name = "bitflags"
 version = "1.2.1"
@@ -69,12 +75,6 @@ dependencies = [
  "regex-automata",
 ]
 
-[[package]]
-name = "byteorder"
-version = "1.4.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "14c189c53d098945499cdfa7ecc63567cf3886b3332b312a5b4585d8d3a6a610"
-
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -107,6 +107,30 @@ dependencies = [
  "crossbeam-utils",
 ]
 
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94af6efb46fef72616855b036a624cf27ba656ffc9be1b9a3c931cfc7749a9a9"
+dependencies = [
+ "cfg-if",
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4ec02e091aa634e2c3ada4a392989e7c3116673ef0ac5b72232439094d73b7fd"
+dependencies = [
+ "cfg-if",
+ "crossbeam-utils",
+ "lazy_static",
+ "memoffset",
+ "scopeguard",
+]
+
 [[package]]
 name = "crossbeam-utils"
 version = "0.8.5"
@@ -136,24 +160,22 @@ dependencies = [
  "ansi_term 0.12.1",
  "assert_cmd",
  "clap",
- "crossbeam-channel",
- "ignore",
  "lscolors",
  "num_cpus",
+ "rayon",
  "stfu8",
  "tempfile",
  "terminal_size",
  "thousands",
  "unicode-width",
- "walkdir",
  "winapi-util",
 ]
 
 [[package]]
-name = "fnv"
-version = "1.0.7"
+name = "either"
+version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
+checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
 
 [[package]]
 name = "getrandom"
@@ -166,19 +188,6 @@ dependencies = [
  "wasi",
 ]
 
-[[package]]
-name = "globset"
-version = "0.4.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c152169ef1e421390738366d2f796655fec62621dabbd0fd476f905934061e4a"
-dependencies = [
- "aho-corasick",
- "bstr",
- "fnv",
- "log",
- "regex",
-]
-
 [[package]]
 name = "hermit-abi"
 version = "0.1.18"
@@ -188,24 +197,6 @@ dependencies = [
  "libc",
 ]
 
-[[package]]
-name = "ignore"
-version = "0.4.17"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b287fb45c60bb826a0dc68ff08742b9d88a2fea13d6e0c286b3172065aaf878c"
-dependencies = [
- "crossbeam-utils",
- "globset",
- "lazy_static",
- "log",
- "memchr",
- "regex",
- "same-file",
- "thread_local",
- "walkdir",
- "winapi-util",
-]
-
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -214,18 +205,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.95"
+version = "0.2.97"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "789da6d93f1b866ffe175afc5322a4d76c038605a1c3319bb57b06967ca98a36"
-
-[[package]]
-name = "log"
-version = "0.4.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "51b9bbe6c47d51fc3e1a9b945965946b4c44142ab8792c50835a980d362c2710"
-dependencies = [
- "cfg-if",
-]
+checksum = "12b8adadd720df158f4d70dfe7ccc6adb0472d7c55ca83445f6a5ab3e36f8fb6"
 
 [[package]]
 name = "lscolors"
@@ -242,6 +224,15 @@ version = "2.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b16bd47d9e329435e309c58469fe0791c2d0d1ba96ec0954152a5ae2b04387dc"
 
+[[package]]
+name = "memoffset"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "59accc507f1338036a0477ef61afdae33cde60840f4dfe481319ce3ad116ddf9"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "num_cpus"
 version = "1.13.0"
@@ -252,12 +243,6 @@ dependencies = [
  "libc",
 ]
 
-[[package]]
-name = "once_cell"
-version = "1.7.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "af8b08b04175473088b46763e51ee54da5f9a164bc162f615b91bc179dbf15a3"
-
 [[package]]
 name = "ppv-lite86"
 version = "0.2.10"
@@ -292,9 +277,9 @@ dependencies = [
 
 [[package]]
 name = "rand"
-version = "0.8.3"
+version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ef9e7e66b4468674bfcb0c81af8b7fa0bb154fa9f28eb840da5c447baeb8d7e"
+checksum = "2e7573632e6454cf6b99d7aac4ccca54be06da05aca2ef7423d22d27d4d4bcd8"
 dependencies = [
  "libc",
  "rand_chacha",
@@ -304,9 +289,9 @@ dependencies = [
 
 [[package]]
 name = "rand_chacha"
-version = "0.3.0"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e12735cf05c9e10bf21534da50a147b924d555dc7a547c42e6bb2d5b6017ae0d"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
 dependencies = [
  "ppv-lite86",
  "rand_core",
@@ -314,27 +299,52 @@ dependencies = [
 
 [[package]]
 name = "rand_core"
-version = "0.6.2"
+version = "0.6.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "34cf66eb183df1c5876e2dcf6b13d57340741e8dc255b48e40a26de954d06ae7"
+checksum = "d34f1408f55294453790c48b2f1ebbb1c5b4b7563eb1f418bcfcfdbb06ebb4e7"
 dependencies = [
  "getrandom",
 ]
 
 [[package]]
 name = "rand_hc"
-version = "0.3.0"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3190ef7066a446f2e7f42e239d161e905420ccab01eb967c9eb27d21b2322a73"
+checksum = "d51e9f596de227fda2ea6c84607f5558e196eeaf43c986b724ba4fb8fdf497e7"
 dependencies = [
  "rand_core",
 ]
 
 [[package]]
-name = "redox_syscall"
-version = "0.2.8"
+name = "rayon"
+version = "1.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "742739e41cd49414de871ea5e549afb7e2a3ac77b589bcbebe8c82fab37147fc"
+checksum = "c06aca804d41dbc8ba42dfd964f0d01334eceb64314b9ecf7c5fad5188a06d90"
+dependencies = [
+ "autocfg",
+ "crossbeam-deque",
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d78120e2c850279833f1dd3582f730c4ab53ed95aeaaaa862a2a5c71b1656d8e"
+dependencies = [
+ "crossbeam-channel",
+ "crossbeam-deque",
+ "crossbeam-utils",
+ "lazy_static",
+ "num_cpus",
+]
+
+[[package]]
+name = "redox_syscall"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ab49abadf3f9e1c4bc499e8845e152ad87d2ad2d30371841171169e9d75feee"
 dependencies = [
  "bitflags",
 ]
@@ -352,12 +362,9 @@ dependencies = [
 
 [[package]]
 name = "regex-automata"
-version = "0.1.9"
+version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae1ded71d66a4a97f5e961fd0cb25a5f366a42a41570d16a763a69c092c26ae4"
-dependencies = [
- "byteorder",
-]
+checksum = "6c230d73fb8d8c1b9c0b3135c5142a8acee3a0558fb8db5cf1cb65f8d7862132"
 
 [[package]]
 name = "regex-syntax"
@@ -375,13 +382,10 @@ dependencies = [
 ]
 
 [[package]]
-name = "same-file"
-version = "1.0.6"
+name = "scopeguard"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
-dependencies = [
- "winapi-util",
-]
+checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 
 [[package]]
 name = "stfu8"
@@ -449,15 +453,6 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3bf63baf9f5039dadc247375c29eb13706706cfde997d0330d05aa63a77d8820"
 
-[[package]]
-name = "thread_local"
-version = "1.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8018d24e04c95ac8790716a5987d0fec4f8b27249ffa0f7d33f1369bdfb88cbd"
-dependencies = [
- "once_cell",
-]
-
 [[package]]
 name = "treeline"
 version = "0.1.0"
@@ -485,17 +480,6 @@ dependencies = [
  "libc",
 ]
 
-[[package]]
-name = "walkdir"
-version = "2.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "808cf2735cd4b6866113f648b791c6adc5714537bc222d9347bb203386ffda56"
-dependencies = [
- "same-file",
- "winapi",
- "winapi-util",
-]
-
 [[package]]
 name = "wasi"
 version = "0.10.2+wasi-snapshot-preview1"