Motivation:

The result of `header.size()` is already cached in `headerSize`. There is no need to call it again actually.

Modification:

Replace the second `header.size()` with `headerSize` directly.

Result:

Improve performance slightly.

* '4.1' of github.com:netty/netty:
  Support session cache for client and server when using native SSLEngine implementation (netty#10331)
  Simple fix typo (netty#10403)
  Eliminate a redundant method call in HpackDynamicTable.add(...) (netty#10399)
  jdk.tls.client.enableSessionTicketExtension must be respected by OPENSSL and OPENSSL_REFCNT SslProviders (netty#10401)

* '4.1-read' of github.com:Kvicii/netty: (43 commits)
  Make the TLSv1.3 check more robust and not depend on the Java version… (netty#10409)
  Reduce the scope of synchronized block in PoolArena (netty#10410)
  Add IndexOutOfBoundsException error message (netty#10405)
  Add default handling for switch statement (netty#10408)
  Review PooledByteBufAllocator in respect of jemalloc 4.x changes and update allocate algorithm.(netty#10267)
  Support session cache for client and server when using native SSLEngine implementation (netty#10331)
  Simple fix typo (netty#10403)
  Eliminate a redundant method call in HpackDynamicTable.add(...) (netty#10399)
  jdk.tls.client.enableSessionTicketExtension must be respected by OPENSSL and OPENSSL_REFCNT SslProviders (netty#10401)
  重新编译4.1分支
  [maven-release-plugin] prepare for next development iteration
  [maven-release-plugin] prepare release netty-4.1.51.Final
  Correctly return NEED_WRAP if we produced some data even if we could not consume any during SSLEngine.wrap(...) (netty#10396)
  Modify OpenSSL native library loading to accommodate GraalVM (netty#10395)
  Update to netty-tcnative 2.0.31.Final and make SslErrorTest more robust (netty#10392)
  Add option to HttpObjectDecoder to allow duplicate Content-Lengths (netty#10349)
  Add detailed error message corresponding to the IndexOutOfBoundsException while calling getEntry(...) (netty#10386)
  Do not report ReferenceCountedOpenSslClientContext$ExtendedTrustManagerVerifyCallback.verify as blocking call (netty#10387)
  Add unit test for HpackDynamicTable. (netty#10389)
  netty用于测试的内嵌Channel | ChannelInboundHandler主要方法
  ...

…y#10399)

Motivation:

The result of `header.size()` is already cached in `headerSize`. There is no need to call it again actually.

Modification:

Replace the second `header.size()` with `headerSize` directly.

Result:

Improve performance slightly.