diff --git a/rust/Cargo.lock b/rust/Cargo.lock
index 15cc7bc..eac568d 100644
--- a/rust/Cargo.lock
+++ b/rust/Cargo.lock
@@ -44,6 +44,11 @@ name = "autocfg"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "autocfg"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "backtrace"
 version = "0.3.13"
@@ -465,7 +470,7 @@ dependencies = [
  "float-cmp 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "indexmap 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "indexmap 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.59 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -487,13 +492,18 @@ dependencies = [
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "http 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
- "indexmap 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "indexmap 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "string 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "hashbrown"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "hostname"
 version = "0.1.5"
@@ -577,8 +587,12 @@ dependencies = [
 
 [[package]]
 name = "indexmap"
-version = "1.0.2"
+version = "1.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "autocfg 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hashbrown 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
 
 [[package]]
 name = "iovec"
@@ -1207,7 +1221,7 @@ name = "serde_json"
 version = "1.0.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "indexmap 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "indexmap 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "itoa 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "ryu 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.90 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1777,6 +1791,7 @@ dependencies = [
 "checksum arrayvec 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)" = "92c7fb76bc8826a8b33b4ee5bb07a247a81e76764ab4d55e8f73e3a4d8808c71"
 "checksum atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "9a7d5b8723950951411ee34d271d99dddcc2035a16ab25310ea2c8cfd4369652"
 "checksum autocfg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a6d640bee2da49f60a4068a7fae53acde8982514ab7bae8b8cea9e88cbcfd799"
+"checksum autocfg 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 "checksum backtrace 0.3.13 (registry+https://github.com/rust-lang/crates.io-index)" = "b5b493b66e03090ebc4343eb02f94ff944e0cbc9ac6571491d170ba026741eb5"
 "checksum backtrace-sys 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)" = "797c830ac25ccc92a7f8a7b9862bde440715531514594a6154e3d4a54dd769b6"
 "checksum bacon_rajan_cc 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "e85b9d6e723a8216dc9b06725af44e2d4a33020322220dc709753b013ee31fec"
@@ -1825,6 +1840,7 @@ dependencies = [
 "checksum futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)" = "45dc39533a6cae6da2b56da48edae506bb767ec07370f86f70fc062e9d435869"
 "checksum futures-cpupool 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "ab90cde24b3319636588d0c35fe03b1333857621051837ed769faefb4c2162e4"
 "checksum h2 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "ddb2b25a33e231484694267af28fec74ac63b5ccf51ee2065a5e313b834d836e"
+"checksum hashbrown 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "00d63df3d41950fb462ed38308eea019113ad1508da725bbedcd0fa5a85ef5f7"
 "checksum hostname 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "21ceb46a83a85e824ef93669c8b390009623863b5c195d1ba747292c0c72f94e"
 "checksum http 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)" = "1a10e5b573b9a0146545010f50772b9e8b1dd0a256564cc4307694c68832a2f5"
 "checksum httparse 1.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "e8734b0cfd3bc3e101ec59100e101c2eecd19282202e87808b3037b442777a83"
@@ -1832,7 +1848,7 @@ dependencies = [
 "checksum hyper-rustls 0.16.1 (registry+https://github.com/rust-lang/crates.io-index)" = "15b66d1bd4864ef036adf2363409caa3acd63ebb4725957b66e621c8a36631a3"
 "checksum ident_case 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3c9826188e666f2ed92071d2dadef6edc430b11b158b5b2b3f4babbcc891eaaa"
 "checksum idna 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "38f09e0f0b1fb55fdee1f17470ad800da77af5186a1a76c026b679358b7e844e"
-"checksum indexmap 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7e81a7c05f79578dbc15793d8b619db9ba32b4577003ef3af1a91c416798c58d"
+"checksum indexmap 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "55e2e4c765aa53a0424761bf9f41aa7a6ac1efa87238f59560640e27fca028f2"
 "checksum iovec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "dbe6e417e7d0975db6512b90796e8ce223145ac4e33c377e4a42882a0e88bb08"
 "checksum ipconfig 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "08f7eadeaf4b52700de180d147c4805f199854600b36faa963d91114827b2ffc"
 "checksum itoa 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "1306f3464951f30e30d12373d31c79fbd52d236e5e896fd92f96ec7babbbe60b"
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 5b9ab7c..8910811 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -37,7 +37,7 @@ float-cmp = "0.4.0"
 bacon_rajan_cc = "0.2.4"
 newtype_derive = "0.1.6"
 custom_derive = "0.1.7"
-indexmap = "1.0.2"
+indexmap = "1.6.0"
 owning_ref = "0.4.0"
 fnv = "1.0.6"